In Allah's sight the most disgusted among the people is a person who submits to Faith and then disbelieves.
قال رسول الله صلّ الله علیه و آله
أبغضُ الخلقِ إلی الله مَن آمَنَ ثمّ کَفَرَ
منفور ترین مردم پیش خدا آن کس است که ایمان آورد و سپس کافر شود
“ I define Islam for you in a way that nobody dared do it before me. Islam means obedience to Allah, obedience to Allah means having sincere faith in Him, such a faith means to believe in His Power, belief in His Power means recognizing and accepting His Majesty, acceptance of His Majesty means fulfilling the obligations laid down by Him and fulfillment of obligations means actions (Therefore, Islam does not mean mere faith, but faith plus deeds).” Imam Ali (P.B.U.H)