Enjoin Good and Forbid Evil!
A man came to Umar Ibn Al-Khattab رضي الله عنه at the prophet's mosque and he told him that there is a man who is sat outside and he never joined the congregation for the prayer, Umar replied, "Okay, let's go see him." Umar went to him and inquired as to why he didn't join in the congregational prayer, the man replied to Umar saying, "that's not your business, go mind your business!" Umar always used to carry a stick around with him, so Umar put the man down and beat him with the stick, then Umar replied, "just to let you know...this is my job, it is my business!!" - Shaykh Musa Jibril حفظه الله