(Or think ye that ye will enter paradise…) [2:214].
Qatadah and al-Suddi said: “This verse was revealed about the Battle of the Ditch when Muslims were stricken with exhaustion, hardship, heat, fear, cold, tightness of living and all kinds of harm. And it was as Allah, exalted is He, described: (… and hearts reached to the throats…) [33:10]”.
Said 'Ata': “When the Messenger of Allah, Allah bless him and give him peace, and his Companions migrated to Medina, the Muslims lived under extreme duress because they migrated without their wealth and had left their houses and fortunes in the hands of the idolaters, preferring instead the good pleasure of Allah and His Messenger. Additionally, the Jews manifested their enmity to the Messenger of Allah, Allah bless him and give him peace, and a number of wealthy people were hypocrites in secret. In order to set their minds at rest, Allah, exalted is He, revealed (Or think ye that ye will enter paradise…)”.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou