Blocking the Gaps in the Rows and Joining the Feet

Question:
Honorable Shaykh, may Allah grant you success, a questioner asks: Is it obligatory to block the gaps in the rows during prayer and to join the feet together?

Answer:
Yes, blocking the gaps is obligatory. The Prophet (peace and blessings be upon him) said: Satan slips in between the worshippers and whispers to them. If they close ranks and block the gaps, Satan cannot get in among them. Yes, but blocking the gaps does not mean you spread your legs to take up the space of two men. Blocking the gaps is done by standing close together and aligning the shoulders and the ankles. Yes.