English Translation of Al-Quran
.Surah Al-Ahzab [The Confederates]
Ayat 15. And indeed they had already made a covenant with Allah not to turn their backs, and a covenant with Allah must be answered for.
Ayat 16. Say (O Muhammad ﷺ [SAWW](PBUH) to these hypocrites who ask your permission to run away from you): “Flight will not avail you if you flee from death or killing, and then you will enjoy no more than a little while!”
Tafseer of Surah Al Ahzab (The Confederates) Ayat 15 & 16. And yet they had already covenanted with Allah not to turn their backs, and a covenant with Allah must (surely) be answered for. Apparently, after the battle of Uhud, certain men who had then shown cowardice were forgiven for undertaking that they would behave better next time. A solemn promise made to the Messenger of Allah is a promise to Allah, and it cannot be broken with impunity. Ayat 16. Say: “Running away will not profit you if ye are running away from death or slaughter; and even if (ye do escape), no more than a brief (respite) will ye be allowed to enjoy!” The coward in a fight does not usually save himself from death. He is subject, after desertion, to the fury both of the enemy and of his own side for cowardice and desertion. Assuming that he did escape with his life, where could he go? The brand of cowardice will be on him, and he will be subject to the vengeance of his own people. In any case, his life would be in ignominy and would be brief, and he would have irretrievably lost the need of valor.
English Translation of Hadith
Hazrat Abu Hurairah (May Allah be pleased with him) reported: The Messenger of Allah ﷺ [SAWW](PBUH) said, “Keep away from the seven fatalities” It was asked: “What are they, O Messenger of Allah?” He ﷺ[SAWW](PBUH) replied, “Associating anything with Allah in worship (i.e., committing an act of Shirk), sorcery, killing of one whom Allah has declared inviolable without a just cause, devouring the property of an orphan, the eating of usury (Riba), fleeing from the battlefield and accusing chaste believing women, who never even think of anything touching their chastity.”
[Al-Bukhari Book 04, Chapter 51, Hadith # 028]
Lesson: as mentioned above in Surah Al-Ahzab Ayat 16. these hypocrites who ask your permission to run away from you): “Flight will not avail you if you flee from death or killing,” All the sins mentioned in the Hadith are major sins but shirk is the greatest of all. The reason behind this is that it will never be pardoned, and one who commits it, will abide in Hell for all eternity. So far as the other major sins are concerned with Allah, He may forgive them if He so wills; otherwise one who is guilty of such sins will have to suffer the torments of Hell. He will, however, be sent to Jannah after suffering the punishment if he is a Muslim.