Do we become angels after we die?

Angels are beings created by God (Colossians 1:15-17) and are entirely
different from humans. They are God's special agents to carry out His
plan and to minister to the followers of Christ (Hebrews 1:13-14).
There is no indication that angels were formerly humans or anything
else—they were created as angels. Angels have no need of, and cannot
experience, the redemption that Christ came to provide for the human
race. First Peter 1:12 describes their desire to look into the Gospel,
but it is not for them to experience. Had they been formerly humans,
the concept of salvation would not be a mystery to them, having
experienced it themselves. Yes, they rejoice when a sinner turns to
Christ (Luke 15:10), but salvation in Christ is not for them.

Eventually, the body of the believer in Christ will die. What happens
then? The spirit of the believer goes to be with Christ (2 Corinthians
5:8). The believer does not become an angel. It is interesting that
both Elijah and Moses were recognizable on the Mount of
Transfiguration. They had not transformed into angels, but appeared as
themselves—although glorified—and were recognizable to Peter, James
and John.

In 1 Thessalonians 4:13-18, Paul tells us that believers in Christ are
asleep in Jesus; that is, their bodies are dead, but their spirits are
alive. This text tells us that when Christ returns, He will bring with
Him those who are asleep in Him, and then their bodies will be raised,
made new like Christ's resurrected body, to be joined with their
spirits which He brings with Him. All believers in Christ who are
living at the return of Christ will have their bodies changed to be
like Christ, and they will be completely new in their spirits, no
longer having a sin nature.

All the believers in Christ will recognize one another and live with
the Lord forever. We will serve Him throughout eternity, not as
angels, but along with the angels. Thank the Lord for the living hope
He provides for the believer in Jesus Christ.