At-Tawbah 9:37

Innama annasee-o ziyadatunfee alkufri yudallu bihi allatheena kafaroo yuhilloonahuAAaman wayuharrimoonahu AAaman liyuwati-ooAAiddata ma harrama Allahu fayuhillooma harrama Allahu zuyyina lahum soo-o aAAmalihimwallahu la yahdee alqawma alkafireen

Indeed, the postponing [of restriction within sacred months] is an increase in disbelief by which those who have disbelieved are led [further] astray. They make it lawful one year and unlawful another year to correspond to the number made unlawful by Allāh and [thus] make lawful what Allāh has made unlawful. Made pleasing to them is the evil of their deeds; and Allāh does not guide the disbelieving people.

Nasī’ (i.e. postponement of months) is nothing but a further excess in infidelity, whereby the disbelievers are misguided. They allow it one year and disallow it another year, so that they may conform (only) to the number of what Allah has sanctified, and allow what Allah has disallowed. The evil of their deeds has been beautified for them (by Satan). And Allah does not lead the disbelieving people to the right path.