Is the action of a Companion considered a Sunnah if the Prophet (peace and blessings be upon him) remained silent about it?

Question:
He says: Honorable Shaykh, may Allah grant you success. If a Companion performed an action during the time of the Prophet (peace and blessings be upon him), and it is not known that the Prophet (peace and blessings be upon him) approved of it or forbade it, is the Companion's action considered part of the Sunnah?

Answer:
It is considered an approval (taqrir) if a Companion performed an act of worship during the time of the Prophet (peace and blessings be upon him). This is an approval because the Sunnah is divided into categories. The Sunnah is what is established from the Prophet (peace and blessings be upon him) by way of speech, action, or approval. The Messenger (peace and blessings be upon him) received revelation; if what this Companion did had not been permissible, revelation would have descended upon the Messenger (peace and blessings be upon him) to alert this person.