What are evil deeds, and what are sins, and do good deeds have ranks, and what must a Muslim do to reach the best of them?

Ibn al-Qayyim differentiated between sins (dhunūb) and evil deeds (sayyi’āt), and between forgiveness (maghfirah) and expiation (takfīr). Sins (dhunūb) refer to major sins (kabā’ir), while evil deeds (sayyi’āt) refer to minor sins (saghā’ir). Expiation (takfīr) of evil deeds occurs by avoiding major sins or by performing acts of obedience such as prayer (salāh) and fasting (ṣawm). As for forgiveness (maghfirah), it pertains to major sins. The term 'maghfirah' (forgiveness) is more general and comprehensive, and when used in isolation, each term can encompass the other.

Regarding good deeds (ḥasanāt), they are of varying ranks, including the obligatory (wājib) and the supererogatory (mustaḥabb). A Muslim should prioritize performing the obligatory deeds first, then engage extensively in supererogatory acts. If two acts of worship conflict, one should prioritize the more preponderant and important one, because preoccupation with a lesser act over a superior one is among the stratagems of Satan. Only people of insight and knowledge who can distinguish between the ranks of deeds can overcome this obstacle.