It is reported that ‘Alī b. Abī Ṭālib – Allāh be pleased with him – said, “The servant [of Allāh] should not fear except his sins, and should not hope except in his Lord. The ignorant should not be ashamed to ask, and the knowledgeable should not be ashamed to say – if he does not know something – ‘Allāh knows best.’ Patience (al-ṣabr) to faith (Al-Īmān) is like the head to the rest of the body: if the head is cut off, the body will rot. And one who has no patience, has no faith.”

Al-Baihaqī, Shu’ab Al-Īmān, Vol.12 p195.