Explanation

This Hadīth informs us that the Prophet (may Allah's peace and blessings be upon him) took for himself a room made of straw mats in a corner of the mosque. Apparently, he was observing I‘tikāf and was performing Qiyām in that room. When some Muslims heard him pray, they stood in rows behind him in congregation. They kept doing this for some nights until one night they did not hear his voice. They thought he was asleep so they started to make some sounds so as to wake him up. The Prophet (may Allah's peace and blessings be upon him) came out to them and told them that he was not asleep, but that he feared that if they kept doing this, the voluntary night prayer would become obligatory upon them. He further explained that if it became obligatory to perform the night prayer, they would not be able to observe it. He also informed them that the best voluntary prayer is that offered in one’s house.