Rambam - Book of Love - Laws of Prayer - Chapter 15

This is the second book of the Mishneh Torah of the Rambam, Rabbi Moshe ben Maimon. Laws of Tefillah.
This chapter explains the things that impede the blessing of the Kohanim, who does not have any of those things that impede and is not careful with the precepts, whether the blessing of the Kohanim requires a quorum of ten and a synagogue where everyone is a Kohanim or which has no Kohanim, the law of a Kohen who has already blessed once, whether he can bless again that day, a Kohen who did not move from his place when the messenger of the congregation arrived for the corresponding blessing, who did not go up to bless at all.