Tafsir of An-Nisa' 4:38

(And those who spend their wealth to be seen by the people), meaning: for the sake of showing off and for the sake of what is said, not for the sake of Allah, the Great, the Most High. The relative pronoun is conjoined to its counterpart [the one previously mentioned] or to "the disbelievers." They share in the condemnation and the threat because stinginess and extravagance—which is spending on what is not appropriate—are both extremes of excess and negligence, equal in their loathsomeness and in attracting censure. It is also permitted that it be an initial subject whose predicate is omitted, meaning: "their companion is Satan," as the subsequent discourse indicates.

(And ri'a' [showing off]) is an infinitive in the accusative case, serving as a circumstantial qualifier (hal) for the pronoun in (yunfiqun). Its genitive construction with "the people" is an instance of an infinitive attributed to its object, meaning: "showing off to the people."

(And they do not believe in Allah), the One capable of rewarding and punishing, (nor in the Last Day), in which the obedient is rewarded and the disobedient is punished, so that they might intend through their spending that which would cause its branches to flourish and its fruit to be harvested. They are the Jews—and this has been narrated from Mujahid—or the polytheists of Mecca, or the hypocrites, as has been said.

(And whoever has Satan)—and what is meant by him is Iblis and his aides, both internal and external, from his tribe and the people who follow him, or from the psychological faculties, desires, the company of evil-doers, or from the soul, animalistic faculties, and the devils of mankind and jinn—(as a companion), meaning: as an associate and intimate friend in this world, (then evil), meaning: how evil is the Satan or the companion—(is he as a companion), because he invites him to the disobedience that leads to the Fire. "Evil" (sa'a) has been transferred to the category of "praiseworthy" (ni'ma) and "blameworthy" (bi'sa), and is thus treated as an indeclinable verb; for this reason, it is connected with the particle fa. It is also possible that it remains in its original category, with the omission of the particle qad, as in His saying, Glory be to Him: "And whoever comes with an evil deed, their faces will be cast into the Fire." The purpose of this sentence is to alert them that Satan is their companion, so he urged them to that [behavior] and beautified it for them. It is also permitted that this is a threat to them that Satan will be paired with them on the Day of Resurrection in the Fire, where they will curse and hate one another, and their regret will reach its peak.