How were angels created and how do they propagate?

This theory of the origin of the angels was disputed and others put forward.

From every utterance that issues from the mouth of the Holy One, blessed be He, an angel is created; as it is said, "By the word of the Lord were the heavens made" and all the "host of them by the breath of his mouth."[1]

According to another view, angels were constituted of the same elements as heaven itself: "An angel consists half of water and half of fire, and possesses five wings."[2]

The general belief was that angels were immortal and did not propagate their species.[3] On occasion, however, God may destroy numbers of them when they withstand His will.[4]

footnotes [1] Psalms 33:6; BT Hagiga 14a
[2] BT Rosh Hashanah 58A
[3] Genesis Rabbah 8:2
[4] BT Sanhedrin 38B