Eman has six pillars. To deny any one of the pillars, in part, or in whole, is the same as denying everything–it takes you out of Islam, and may Allah protect us all from that.
The pillars are:
- Allah: Believe that Allah, Lord of the Worlds, exists, and believe in his asmaa wal sifa.
- Books: Believe in all the divine revelation, including the Torah, the Injeel, and the Qur’an. They are really the same book (but now, the original Torah and Injeel no longer exist).
- Angels: Believe in the angels.
- Prophets: Believe in all the Prophets, from Adam (alayhi salaam), the first man and first prophet of Allah, to Muhammad (صلي الله عليه وسلم), the seal of prophets, and everything in-between.
- Qadr: Believe in qadr (fate/predestination/free will)
- Day of Judgement: Believe in the Day of Judgement, and more generally, in the akhira.
Each of these pillars has more depth to them, but this is the general meaning. And I repeat: to deny any pillar (or any part of any pillar) is to leave Islam.
May Allah make us those who live and die on Islam. Ameen.