the believers are those who believe in god and his messenger and then have not doubted and strive for gods cause with their wealth and their persons. these are the sincere.
إنما المؤمنون الذين آمنوا بالله ورسوله ثم لم يرتابوا وجاهدوا بأموالهم وأنفسهم في سبيل الله أولئك هم الصادقون