How do we distinguish between the Sunnah of custom and the Sunnah of worship?

The questioner : How do we distinguish between the Sunnah of custom and the Sunnah of worship?

The Shaykh : Praise be to Allah. I referred earlier to the answer to this question. When I gave the example of the short garment, we said that the Messenger (peace and blessings be upon him) made it part of the believer’s appearance for his garment to reach the middle of the calves, and then he permitted him to lengthen it to above the ankles. So, if there is in what the Messenger (peace and blessings be upon him) did a verbal or practical indication that takes that action out of being a Sunnah of custom, it is said to be a Sunnah of worship; otherwise, it remains a Sunnah of custom. There must be an indication there that points to it being an act of worship.