the word “’Iman (Belief)” is to believe, and Religiously it means a specific belief which is to believe in all what the Prophet sallallahu ^alayhi wa sallam came with.
The Prophet sallallahu ^alayhi wa sallam said: "أَنْ تُؤْمِنَ باللهِ وَمَلاَئِكَتِهِ وَكُتُبِهِ وَرُسُلِهِ واليَوْمِ الآخِرِ وَتُؤْمِنَ بالقَدَرِ خَيْرِهِ وَشَرِّهِ" It means: “To believe in Allah, His Angels, His Revealed Books, His Messengers, the Last Day,…