If you do not go forth, He will punish you with a painful punishment and will replace you with another people, and you will not harm Him at all. And Allāh is over all things competent.
Admonishing clinging to Life rather than rushing to perform Jihad
Allah admonishes those who lagged behind the Messenger of Allah ﷺ in the battle of Tabuk, at a time when fruits were ripe and shades tempting in the intense and terrible heat,
(O you who believe! What is the matter with you, that when you are asked to march forth in the cause of Allah), if you are called to perform Jihad in the cause of Allah,
اثَّاقَلْتُمْ إِلَى الاٌّرْضِ
(you cling heavily to the earth), reclining to remain in peace, shade and ripe fruits.
It is interesting that the modern world would very much like to eradicate crimes but it would do so by not having to bother about God and the Hereafter. To achieve this purpose, it invents, introduces and surrounds itself with things to live with - a lifestyle which would never allow human beings to turn their attention towards God and Hereafter. The result of this negative approach is no mystery. We are watching it with our own eyes. Even in the face of ever better laws, all legal systems seem to be failing. Crimes are there as they were, in fact, they are increasing with dangerous speed. To conclude, we wish that intelligent people among countries and nations of the world would think of using this Qur'anic prescription, at least for once, and discover for themselves how easily crimes can be controlled.
Now, as we move to the second verse (39), the text has, after serving a notice of warning to the lazy and the listless about their disease and its treatment, delivered its verdict by saying:
` If you do not come out for Jihad, Allah will have you go through a painful punishment and bring in your place a nation other than you, and (by your refusal to follow Islam) you can bring no loss to Allah (or His Messenger) because Allah is powerful over everything.'
Tazkirul Quran
Maulana Wahiduddin Khan
These verses were revealed while the Prophet was at Tabuk (9 Hijra). At this juncture the behaviour displayed by the hypocrites (munafiqun) of Madinah gives us an idea of the role played by people of fickle faith when they join the Islamic society. In reality there are two stages of connection with Islam. In one, all of man’s loyalties become attached to Islam; it becomes a question of life and death for him. In the other, man’s real interests are elsewhere and he only superficially accepts Islam. In the first category are the real believers—the people of faith. In the second are those known, in the terminology of the Shariah, as munafiq (hypocrites). The condition of the believer is that he steadfastly holds to Islam in normal circumstances as well as at times when sacrifice is required. By contrast, the hypocrite seems to be very much to the fore in making a show of his religiousness, when Islam makes no special demands on him, but as soon as he has to fulfil demands of Islam at the level of sacrifice, he backs away.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.