Tafsir of An-Nisa' 4:74

(Let those who exchange the life of this world for the Hereafter fight in the way of Allah). The relative pronoun [alladhina] is the subject of the verb, and the indirect object has been placed before it for the sake of importance. Yashruna (يشرون) is the present tense of shara (شرى), and it is among the words with opposite meanings (addad), capable of meaning both "to sell" and "to buy."

If it means "they buy," then the intended meaning of the relative pronoun is the hypocrites, who are commanded to abandon hypocrisy and join the believers in striving. The fa (ف) is for sequential consequence, meaning: it is necessary, after the discouraging and hypocrisy that has emanated from them, to abandon it and rectify what has been missed of Jihad.

If it means "they sell," then the intended meaning is the believers who have forsaken the world and chosen the Hereafter. They are commanded to remain steadfast in fighting and to pay no heed to the discouragement of those who discourage them. The fa is the response to an implied condition, meaning: if the hypocrites discourage them, then let them fight and pay no mind [to the hypocrites].

(And whoever fights in the way of Allah and is killed or is victorious, We shall bestow upon him a great reward). And there is—and it is inevitable—an increase in attention within this shift in address.

The quantity and quality [of this reward] can barely be known. The mention of this reward following the [command for] fighting serves as a reminder that the striving person’s concern should be one of two things: either honoring himself through killing [in battle] and martyrdom, or the strengthening of the religion and the exaltation of the word of Allah, the Exalted, through victory. He should not even consider fleeing in any way. For this reason, it did not say: "or is defeated" (fa-yughlab). The mention of being killed is placed first to indicate its priority in attaining the reward. In the verse, there is a refutation of the one who discourages [others] by saying, "Allah has already bestowed favor upon me," and so forth.