Is a sutrah obligatory in prayer? And what is the distance between it and the one praying?

Question:
Is a sutrah obligatory in prayer? And what is the distance between it and the one praying? And does one who does not place a sutrah during prayer commit a sin?

Answer:
The sutrah is a recommended practice (sunnah), based on his (peace and blessings be upon him) saying: It is the recommended practice (sunnah) to pray facing it, and that the distance between him and it be three cubits or less from his foot, from his foot to its location three cubits or less, and that there be something between him and it when he prostrates, a small amount between him and it; so that he does not reach it. This is the recommended practice (sunnah) and not obligatory; because it is established from him (peace and blessings be upon him) that at some times he prayed without a sutrah, peace and blessings be upon him.