Musannaf Ibn Abi Shaybah

Hazrat Mujahid and Hazrat Ata, may Allah be pleased with them, regarding the command { فَإِذَا قُضِیَتِ الصَّلاَۃُ فَانْتَشِرُوا فِی الأَرْضِ وَابْتَغُوا مِنْ فَضْلِ اللہِ } (When the prayer is finished, disperse in the land and seek the bounty of Allah), state that if one wishes, one may seek the bounty, and if one wishes, one may not.