They fulfill vows, and they fear a Day whose evil will be wide-spreading.meaning, they devote to worship Allah using that which He made obligatory upon them from actions of obligatory obedience that is based on Islamic legislation. They also worship Him by fulfilling their vows.Imam Malik reported from Talhah bin `Abdul-Malik Al-Ayli, who reported from Al-Qasim bin Malik, from `A'ishah that the Messenger of Allah said,مَنْ نَذَرَ أَنْ يُطِيعَ اللهَ فَلْيُطِعْهُ وَمَنْ نَذَرَ أَنْ يَعْصِيَ اللهَ فَلَ يَعْصِهWhoever makes a vow to obey Allah, then he should obey Him.And whoever makes a vow to disobey Allah, then he should not disobey Him.Al-Bukhari also recorded this Hadith from Malik.These people also abandon those forbidden things which He (Allah) has prohibited for them, due to their fear of having an evil reckoning on the Day of Return. This is the Day when the evil will spread out among all people except for those upon whom Allah has had mercy.Ibn `Abbas said, "Spreading."Qatadah said,"By Allah! The evil of that Day will spread until it fills the heavens and the earth."Concerning Allah's statement