Q. Why doesn’t Maimonides list the belief in angels in his 13 Principles?
Others took the idea of angels quite literally; Maimonides rationalised the idea and saw angels as Intelligences or energies which served God and were subservient to Him.
Other Jewish teachers emphasised that the Hebrew word for “angel” literally means “messenger”, and they pointed out that God has many messengers, ranging from prophets to ordinary people who are all capable of carrying out Divinely-appointed tasks. Working for God does not literally make us angels, but there is a beautiful poetical idea that every good deed becomes an angel.