Go ye, then, for four months, backwards and forwards, (as ye will), throughout the land, but know ye that ye cannot frustrate Allah (by your falsehood) but that Allah will cover with shame those who reject Him.
All of the disbelievers and
idolaters of Makkah were allowed a respite of four months to leave the Arabian
peninsula or embrace Islam. This refers to all those who were covered by some
treaty without a fixed time limit and those whose treaties ended in less than
four months. Then they were told to know that they could not escape Allah’s
decision, for He would surely humiliate the disbelievers.
Ahmad, Israr. (2012). Bayan ul Quran. 9-At-Tauba.pdf (islamicweblibrary.com)