An-Nisaa 4:48

Allah does not forgive associating partners with Him[34], but forgives anything less than that for whom He wills. Whoever associates partners with Allah has indeed committed a grave sin.

[34] The Prophet (ﷺ) said: "Allah will say to that person of the Hellfire who will receive the least punishment, ‘If you had everything on the earth, would you give it as a ransom to free yourself?’ He will say, `Yes’. Then Allah will say, ‘While you were in the backbone of Adam, I asked you much less than this, (i.e., not to worship others besides Me), but you insisted on worshiping others besides me.’" [Sahih al-Bukhāri: 551]

Indeed, Allāh does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allāh has certainly fabricated a tremendous sin.

48. Verily, Allâh forgives not that partners should be set up with Him (in worship), but He forgives except that (anything else) to whom He wills; and whoever sets up partners with Allâh in worship, he has indeed invented a tremendous sin.[18]

[18] (V.4:48) Narrated Anas :رضي الله عنه The Prophet صلى الله عليه وسلم said, "Allâh will say to that person of the (Hell) Fire who will receive the least punishment, ‘If you had everything on the earth, would you give it as a ransom to free yourself (i.e. save yourself from this Fire)?’ He will say, `Yes’. Then Allâh will say, `While you were in the backbone of Adam, I asked you much less than this, (i.e. not to worship others besides Me), but you insisted on worshipping others besides me.’" (Sahih Al-Bukhâri, Vol. 4, Hadîth No 551).

Lo! Allah forgiveth not that a partner should be ascribed unto Him. He forgiveth (all) save that to whom He will. Whoso ascribeth partners to Allah, he hath indeed invented a tremendous sin.