I love this part:


A Simple Definition

Angels are spiritual beings created by God to serve Him, though created higher than man. Some, the good angels, have remained obedient to Him and carry out His will, while others, fallen angels, disobeyed, fell from their holy position, and now stand in active opposition to the work and plan of God.
The Nature of Angels
Angels are created beings

The fact of their creation is brought out in Psalm 148. There the psalmist calls upon all in the celestial heavens, including the angels, to praise God. The reason given is, “For He commanded and they were created” (Ps. 148:1-5).

The time of their creation is never stated, however, we know they were created before the creation of the world. From the book of Job we are told that they were present when the earth was created (Job 38:4-7) so their creation was prior to the creation of the earth as described in Genesis one.

The agent of their creation is specifically stated to be Christ as the One who created all things (cf. John 1:1-3 with Col. 1:16).7

The nature of their creation is as a host or a company, simultaneously. Unlike human beings and the animal kingdom created in pairs and who procreate, angels were created simultaneously as a company, a countless host of myriads (Col. 1:16; Neh 9:6). This is suggested by the fact they are not subject to death and they do not or were not to propagate. They are nevertheless an innumerable host created before the creation of the earth (cf. Job. 38:7; Neh. 9:6; Ps 148:2, 5; Heb 12:22; Dan 7:10; Matt 26:53; Rev. 5:11; with Matt. 22:28-30; Luke 20:20-36).

and this...



Angels are spirit creatures

(1) Angels are spirit beings.

Though at times they have been given the ability to reveal themselves in the form of human bodies as in Genesis 18:3, they are described as “spirits” in Hebrews 1:14. This suggests they do not have material bodies as we do. Hence, they do not function as human beings in terms of marriage and procreation (Mark 12:25) nor are they subject to death (Luke 20:36). Mankind, including our incarnate Lord, is “lower than the angels” (Heb. 2:7). Angels are not subject to the limitations of man, especially since they are incapable of death (Luke 20:36). Angels have greater wisdom than man (2 Sam. 14:20), yet it is limited (Matt. 24:36). Angels have greater power than man (Matt. 28:2; Acts 5:19; 2 Pet. 2:11), yet they are limited in power (Dan. 10:13).

pretty much explains their creation and duties