Aqeedah Tahaawiyyah: Lesson 34 : Point 
137.And the servant does not exit from Eemaan except by denying that which entered him into it.
At-Ta`leeqaat Al-Mukhtasarah `alaa Matn Al-`Aqeedah At–Tahaawiyyah. By Shaykh Saalih ibn Fawzaan al-Fawzaan hafizahullaah. Translated by Aboo Talhah Daawood Burbank, rahimahullaah, in 1426AH
Posted with kind permission from Dawud Burbank rahimahullaah
Commentary from Shaykh Ibn Baz : ( from alifta.net)
This restriction should be considered. A disbeliever embraces Islam on the pronunciation of the Two Shahadahs (Testimonies of Faith) if he has not already pronounced them. If he has already pronounced them, he re-embraces Islam by Tawbah (repentance to Allah) for the cause for his disbelief. He may get out of the fold of Islam for many reasons other than ingratitude, as indicated by scholars in the Chapter on the Ruling on the Murtad (Apostate). Such causes include blasphemy against Islam or the Prophet, peace be upon him, or making a mockery of Allah, His Messenger, Book, or anything of His Shar` (Law) for Allah, Exalted be He, says: “Say, ‘Is it Allah and His verses and His Messenger that you were mocking?’ Make no excuse; you have disbelieved after you had believed.“
One of the causes for disbelief is idolatry, supplicating to the dead, making Istighathah (beseeching for help) to them and the like, for this contradicts the testimony of “There is none worthy of Worship except Allah,” which indicates that worship is an exclusive right of Allah Alone.
Other causes for disbelief are making Du`a’ (supplication), Istighathah, Ruku` (bowing), Sujud (Prostration), slaughtering, making a vow, and the like to something other than Allah. He who does any of these things to something other than Allah, including idols, angels, Jinn (creatures created from fire), the dead, and other creatures, commits Shirk (associating others with Allah in His Divinity or worship) and does not act upon the testimony of “There is none worthy of Worship except Allah”.
All such acts bring one out of the fold of Islam, according to the Ijma` (consensus of scholars) of the scholars. These are not merely acts of ingratitude. The evidence for this is derived from the Book of Allah and the Sunnah of the Prophet. There are many other acts that cause a Muslim to be declared a disbeliever and they are not then merely acts of ingratitude. Such acts are cited by the scholars in the Chapter on the Ruling on the Murtad. So you can refer to them. May Allah grant us success.
Listen to the Full Audio Series of Aqeedah Tahaawiyyah:
Explanation of Aqeedah at-Tahaawiyyah – Dawud Burbank [Audio|En]
Book Study Resource : Aqeedah at-Tahaawiyyah – Imam at-Tahaawi