To whom is the phrase "peace be upon him" addressed, and why do we say "may Allah be pleased with them" for the Companions, and is there evidence for that? Is it permissible to say "may Allah be pleased with him" for others besides the Companions? And why do we say "O Allah, send prayers and peace upon our Prophet, his family, and his companions," and what is the significance of mentioning "the family" and "the companions" in it? Did the Messenger command that?

It is said "peace be upon him" for prophets, and the more complete phrase for our Prophet Muhammad (peace and blessings be upon him) is "peace and blessings be upon him" because Allah commanded us to send blessings and salutations upon him. It has been reported that the Prophet (peace and blessings be upon him) said "peace be upon him" regarding some prophets like David, Solomon, Abraham, and Gabriel. Most scholars believe that it is specific to prophets.

As for saying "may Allah be pleased with them" for the Companions, it is because Allah Almighty informed us of His pleasure with them in the Qur'an, and there is no disagreement on the desirability of seeking Allah's pleasure for them. It is permissible to seek Allah's pleasure for others besides the Companions, such as scholars and the righteous, according to the majority view, and this would be a supplication.

As for sending blessings upon the family of the Prophet (peace and blessings be upon him), it is based on his saying in his Tashahhud: "O Allah, bless Muhammad and the family of Muhammad," and his family are those who follow his religion.