The gravest major sins are: associating partners with Allah in worship, feeling secure from Allah's plan, despairing of Allah's mercy, and losing hope in relief coming from Allah

Explanation

The Prophet (may Allah's peace and blessings be upon him) mentioned in this Hadīth the sins that are considered the gravest and worst ones. These sins include associating partners with Allah, the Almighty, in His lordship or His worship. He started with polytheism because it is the gravest sin ever. Another sin is losing hope in Allah’s mercy, because it involves having ill expectations of Allah, and ignorance of the vastness of His mercy. It is one of the gravest sins as well to feel secure against being dragged by way of favors until Allah punishes the sinner all of a sudden. The Hadīth, however, does not aim at listing all the major sins, rather, it aims at highlighting the gravest of them, because the list of major sins contains so many more.

Benefits

• Classification of sins as major and minor sins.
• Shirk is the most fatal and gravest major sin.
• It shows the prohibition of feeling secure of the plan of Allah Almighty and despairing of His mercy, as both of them are from the gravest major sins.
• It is permissible to describe Allah Almighty as Planner against the deceptive planning of other planners. It is an attribute of perfection, as the dispraised planning is the one made against those who do not deserve it.
• A servant should simultaneously be fearful of Allah and hoping for His mercy. When he fears Him, he should not despair of His mercy; and when he hopes for His mercy, he should not totally feel secured.
• Affirming the attribute of mercy for Allah Almighty in a way that befits His majesty.
• It shows the obligation to think positively of Allah Almighty.