Far from an outdated observance, for the Christian, the biblical Feast of Trumpets looks forward to the return of Christ.
Check it out:
Old Covenant Verses of Note:
Leviticus 23:23-25
Numbers 29:1-6
New Covenant Verses of Note:
Matthew 24:29-31
1 Corinthians 15:51-57
1 Thessalonians 4:13-18
Revelation 11:15
