Many people suffer unexplained illnesses, break up of marriages, childbirth defects or stillbirths, breakup of communities, failed businesses etc. never understanding why. Many of us in the West are unaware of the harms of Hasad (Envy) or El 'Ayn (the Evil Eye). The 'ulamaa' (scholars) of the El-Lajnah El-Daa'imah (Standing Committee for Islaamic Research) were asked to define al-ayn. They responded with the following:
"The Arabic word El-'Ayn (the 'ayn) refers to when a person harms another with his eye. It starts when the person likes a thing, then his evil feelings affect it, by means of his repeated looking at the object of his jealousy. Allah commanded His Prophet, Muhammad ﷺ to seek refuge with Him from the haasid (envier), as He said: "And from the evil of the envier when he envies" (El-Falaq 113:5) Fataawa Esh-Shaykh Ibn 'Uthaymeen, 2/117, 118 
“And verily, those who disbelieve would almost make you slip with their eyes (through hatred) when they hear the Reminder (the Qur'an), and they say: "Verily, he is a madman!'' Qur’an.Surah Qalam 68:51 and according to Tafseer ibn kathir, “with their eyes”, meaning, `they are jealous of you due to their hatred of you, and were it not for Allah's protection of you, defending you against them (then their evil eye would harm you).' 
This Ayah is a proof that the effect of the evil eye and its affliction by the command of Allah is real. Many Ahadith have been reported concerning this through Ibn `Abbas رضي الله عنه that Muhammad ﷺ said, The evil eye is real.
It was narrated from Ibn ‘Abbas رضي الله عنه that Muhammad ﷺ said: “The evil eye is real and if anything were to overtake the divine decree, it would be the evil eye. When you are asked to take a bath (to provide a cure) from the influence of the evil eye, you should take a bath.” This was classed as saheeh by Tirmidhi 2059, and also by al-Albaani in al-Silsilah al-Saheehah, 1251.
Ibn 'Abbas رضي الله عنه reported Muhammad ﷺ saying: “The influence of an evil eye is a fact; if anything would precede the destiny it would be the influence of an evil eye, and when you are asked to take bath (as a cure) from the influence of an evil eye, you should take bath.” Sahih Al Muslim 5427
Ibn 'Abbas رضي الله عنه that he said, "Muhammad ﷺ used to invoke Allah's protection for Al-Hasan and Al-Husayn (his grandsons) by saying U’eedhukuma bi kalimaatillahith-taammati min kulli shaytaanin wa haammah wa min kulli ‘aynin laammah (I seek protection for you two by the perfect Words of Allah from every Shaytan, and dangerous creature, and from every eye that is evil.).’” Tirmidhi, 2060; Abu Dawood, 4737. And He would say, “Thus Ibraaheem used to seek refuge with Allah for Ishaaq and Ismaa’eel, peace be upon them both.” Sahih Al Bukhari, Vol 4: 590 and 3371(NE).
'A'isha رضي الله عنه reported that when any of the members of the household fell ill Muhammad ﷺ used to blow over him by reciting Mu'awwidhatan (Surah Falaq and Surah Naas), and when he suffered from illness of which he died I used to blow over him and rubbed his body with his hand for his hand had greater healing power than my hand. Sahih Al Muslim 5439.
Asma’ bint ‘Umays رضي الله عنه said: "O Messenger of Allah! Verily, Bani Ja`far are afflicted with the evil eye; should I seek to have Ruqyah '' The Prophet replied,Yes , for if anything were to overtake the divine decree it would be the evil eye.” Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi 2059.
There are ahaadeeth from Muhammad ﷺ which speak of the effects of the evil eye. For example it is narrated in al-Saheehayn (present in both Bhukari and Muslim) that ‘A'isha رضي الله عنه said: Muhammad ﷺ used to tell me to recite ruqyah for protection against the evil eye. Sahih Al Bukhari Vol 7:634. Fataawa al-Shaykh Ibn ‘Uthaymeen, 2/117, 118 
According to ibn Uthaymin, one of the strong signs that a person is inflicted with the disease of hasad is that he always tries to conceal the virtues and goodness of others. He does not like it when others talk about the good that a person has done. He remains silent and pretends like he does not know of the good that the other one has done. A true believer who is free of hasad likes it when good things are said about others and when the good deeds of others are appreciated and spoken about...He has no envy in his heart for what Allah has bestowed upon the others and, therefore, he spreads that good news to others. [Ibn Uthaymin, Sharh Riyadh, vol. 4, p. 707.]
According to ibn Taimiya, hasad is always accompanied by hatred. This is one of the evils of hasad. First the person is envious of the other person. After some time, this envy develops into hatred. [Ibn Taimiya, Majmu vol. 10, p. 127. 
“There is no practical difference , but the origin of the evil eye is from envy, that is because the one who causes the evil eye – and we seek refuge in Allah – has in his heart envy for the servants of Allah and he does not love any good for anyone. If therefore he sees something from a person that pleases him and he is envious then this emotion eminates from him and afflicts the individual he envies, and that is why Allah said, “و من شر حاسد إذا حسد – And from the evil of the envier when he envies”.
Protection from the evil of the envier and the evil eye:
1 – Trust and dependance in Allah, and that a person does not turn to these affairs and give them importance and concern, rather he shuns away from them.
2 – Using the beneficial supplications mentioned in the Qur’an and Sunnah for they are the best of protection for a person, just like what has been authenticated from Muhammad ﷺ regarding Ayat ul-Kursee and that the one who recites it at night then there will not cease to be a protector upon him and shaytaan will not approach him until he awakens in the morning. shaikh-ibn-ul-uthaymeen 
It was narrated from Sahl ibn Haneef رضي الله عنه that the Prophet (May Allah honor Him and grant Him peace) came out and traveled with him towards Makkah, until they were in the mountain pass of al-Kharaar in al-Jahfah. There Sahl ibn Haneef رضي الله عنه did ghusl, and he was a handsome white-skinned man with beautiful skin. ‘Aamir ibn Rabee’ah رضي الله عنه one of Banu ‘Adiyy ibn Ka’b looked at him whilst he was doing ghusl and said: “I have never seen such beautiful skin as this, not even the skin of a virgin,” and Sahl fell to the ground. They went to Muhammad ﷺ came and said, “O Messenger of Allah, can you do anything for Sahl, because by Allah he cannot raise his head.” He said, “Do you accuse anyone with regard to him?” They said, “ ‘Aamir ibn Rabee’ah looked at him.” So the Messenger of Allah called ‘Aamir and rebuked him strongly. He said, “Why would one of you kill his brother? If you see something that you like, then pray for blessing for him.” Then he said to him, “Wash yourself for him.” So he washed his face, hands, forearms, knees and the sides of his feet, and inside his izaar (lower garment) in the vessel. Then that water was poured over him, and a man poured it over his head and back from behind. He did that to him, then Sahl got up and joined the people and there was nothing wrong with him. Musnad Ahmad 15550, Maalik 1811, al-Nasaa’i and Ibn Hibbaan. Classed as saheeh by al-Albaani in al-Mishkaat, 4562.
It was narrated that Jabir ibn 'Abdullah رضي الله عنه said: Muhammad ﷺ said: "Most of those who die of my Ummah, after the will and decree of Allah, will die because of the evil eye." Narrated by Al-Bukhari in Al-Tarikh, and by Al-Bazzar. Shaykh Al-Albani said: a Hadith Hasan - Sahih Al-Jami', 1217.
Du’aa’s for protection include the following:
A’oodhu bi kalimaat-illaah il-taammati min sharri makhalaqa (I seek refuge in the perfect words of Allah from the evil of that which He has created). Muslim, al-Dhikr wa’l-Du’aa, 4881
A’oodhu bi kalimaat-illaah il-taammati min ghadabihi wa ‘iqaabihi, wa min sharri ‘ibaadihi wa min hamazaat al-shayaateeni wa an yahduroon(I seek refuge in the perfect words of Allah from His wrath and punishment, from the evil of His slaves and from the evil promptings of the devils and from their presence). al-Bukhaari, Ahaadeeth al-Anbiyaa’, 3120 
And one may recite the words of Allah (Glory be to Him): “Hasbi Allahu laa ilaaha illa huwa, ‘alayhi tawakkaltu wa huwa Rabb ul-‘arsh il-‘azeem.” (Allah is sufficient for me. Laa ilaaha illa Huwa (none has the right to be worshipped but He) in Him I put my trust and He is the Lord of the Mighty Throne)” Qur’an.Surah Tawbah 9:129. 
It was narrated from Abu Sa’eed رضي الله عنه that Jibreel used to do ruqyah for Muhammad ﷺ and say, “Bismillaahi arqeeka min kulli shay’in yu’dheeka, min sharri kulli nafsin aw ‘aynin haasid yashfeek, bismillaahi arqeek (In the name of Allah I perform ruqyah for you, from everything that is harming you, from the evil of every soul or envious eye may Allah heal you, in the name of Allah I perform ruqyah for you).” Sahih Al Muslim 5425.
When they like something, some people say “Masha’Allah laa quwwata illa Billaah (That which Allah wills (will come to pass)! There is no power but with Allah)”. They take as evidence for this an ayath inQur’an.Surah Kahf 18:39. 
Muhammad ﷺ used to say: “Allaahumma Rabb al-Naas, adhhib al-ba’s wa’shfi, anta al-Shaafiy, laa shifaa’a illa shifaa’uka, shifaa’an laa yughaadiru saqaman (O Allah, Lord of mankind, remove the evil and grant healing, for You are the Healer. There is no healing except Your healing, which does not leave any sickness).” Abu Dawood, 3883; Ibn Maajah, 3530. This hadeeth was classed as saheeh by al-Albaani in al-Silsilat al-Saheehah, 331 and 2972.
Muhammad ﷺ used to seek refuge with Allaah for himself, and the greatest means of seeking refuge that is available to the Muslim is reading the Book of Allaah, above all the Mi’wadhatayn (the last two Soorahs of the Qur’aan, al-Falaq and al-Naas), Soorat al-Faatihah and Aayat al-Kursiy [al-Baqarah 2:255].
Wearing Qur’aanic ayah or certain shapes, Imaam Ahmad narrated in his Musnad from ‘Uqbah ibn ‘Aamir (may Allaah be pleased with him) that Muhammad ﷺ said: “Whoever wears an amulet, may Allah not fulfil his need, and whoever wears seashells [for protection from the evil eye] may Allah not protect him.” According to another report, a group came to Muhammad ﷺ and he accepted the bay’ah [allegiance] of nine of them, but not from one of them. They said, “O Messenger of Allaah, you accepted the bay’ah of nine and not from this one.” He said, “He is wearing an amulet.” Then he took it in his hand and broke it, and Muhammad ﷺ accepted his bay’ah. He said, “Whoever wears an amulet is guilty of shirk.” (From Fataawa al-‘Ayn wa’l-Hasad, p. 277) 
In fact this is Tawakkul, because Tawakkul means putting one’s trust in Allah (Glory be to Him) whilst also implementing the means that have been permitted or enjoined. The Prophet (May Allah honor Him and grant Him peace) used to seek refuge for al-Hasan and al-Husayn (May Allah pleased with them both), Tirmidhi 2060 and Abu Dawood 4737. And he would say, “Thus Ibraheem used to seek refuge with Allah for Ishaaq and Ismaa’eel, peace be upon them all.” Sahih Al Bukhaari, 3371.
Everyone who puts the 'ayn on another is haasid (envious), but not every haasid puts the 'ayn on another. The word haasid (envier) is more general in meaning than the word 'aa'in (one who puts the 'ayn on another), so seeking refuge with Allaah from the one who envies includes seeking refuge with Him from the one who puts the 'ayn on another. The 'ayn is like an arrow which comes from the soul of the one who envies and the one who puts the 'ayn on another towards the one who is envied and on whom the 'ayn is put; sometimes it hits him and sometimes it misses. If the target is exposed and unprotected, it will affect him, but if the target is cautious and armed, the arrow will have no effect and may even come back on the one who launched it. Adapted from Zaad El-Ma'aad by Ibnul-Qayyim (Rahimuhullaah). 
 Shaykh Muhammad Ibn Saalih al-Uthaymeen – When to say Masha Allah Tabarak Allah: Fatawaa noor ‘ala adarb tape no321