What is the evidence for the obligation of staying overnight in Muzdalifah?

The evidence for the obligation of staying overnight in Muzdalifah is Allah's saying: (Then, when you depart from 'Arafat, remember Allah at al-Mash'ar al-Haram). The default for a command is obligation. As the Prophet, peace and blessings be upon him, said: (Whoever attends this prayer of ours, and stands with us until we depart, and he had stood before that in 'Arafat by night or by day, his Hajj is complete). The Prophet's permission for the weak to depart from Muzdalifah at night indicates the obligation of staying overnight. All of Muzdalifah is a standing place, and staying overnight there is obligatory, not a pillar or a Sunnah.