Al-Anfal - 8:2

إِنَّمَا الْمُؤْمِنُونَ الَّذِينَ إِذَا ذُكِرَ اللّهُ وَجِلَتْ قُلُوبُهُمْ وَإِذَا تُلِيَتْ عَلَيْهِمْ آيَاتُهُ زَادَتْهُمْ إِيمَانًا وَعَلَى رَبِّهِمْ يَتَوَكَّلُونَ
[8:2]
Those only are believers whose hearts become full of fear when Allah is mentioned, and when His communications are recited to them they increase them in faith, and in their Lord do they trust.
For, Believers are those who, when Allah is mentioned, feel a tremor in their hearts, and when they hear His signs rehearsed, find their faith strengthened, and put (all) their trust in their Lord;
They only are the (true) believers whose hearts feel fear when Allah is mentioned, and when His revelations are recited unto them they increase their faith, and who trust in their Lord;