COMMENTARY on 4:48
Mustafa Khattab:

Translation:
Indeed, Allah does not forgive associating others with Him ˹in worship˺,18 but forgives anything else of whoever He wills. And whoever associates others with Allah has indeed committed a grave sin.
Commentary:
18   A person will never be forgiven if they die as a disbeliever. But if they repent before their death and mend their ways, then their repentance will be accepted (see 25:68-70).

 

A. Yusuf Ali:

Translation:
Allah forgiveth not that partners should be set up with Him; but He forgiveth anything else, to whom He pleaseth; to set up partners with Allah is to devise a sin 569 Most heinous indeed.
Commentary:

569  Just as in an earthly kingdom the worst crime is that of treason, as it cuts at the very existence of the State, so in the spiritual kingdom, the unforgivable sin is that of contumacious treason against Allah by putting up Allah's creatures in rivalry against Him. This is rebellion against the essence and source of spiritual Life. It is what Plato would call the "lie in the soul.." But even here, if the rebellion is through ignorance, and is followed by sincere repentance and amendment, Allah's Mercy is always open ( 4:17 ).

 

Muhammad Asad:

Translation:
VERILY, God does not forgive the ascribing of divinity to aught beside Him, although He forgives any lesser sin 64 unto whomever He wills: for he who ascribes divinity to aught beside God has indeed contrived an awesome sin. 65
Commentary:
64  Lit., "anything below that".
65  The continuous stress, in the Qur’an, on God's transcendental oneness and uniqueness aims at freeing man from all sense of dependence on other influences and powers, and thus at elevating him spiritually and bringing about the "purification" alluded to in the next verse. Since this objective is vitiated by the sin of shirk ("the ascribing of divine qualities to aught beside God"), the Qur’an describes it as "unforgivable" so long as it is persisted in, i.e., unless and until the sinner repents (cf. verses 17 and 18 of this surah).