'First born' in the Bible

And again when he brings the firstborn into the world he says, And let all the agents of God worship him.

By faith he performed the Passover and the sprinkling of the blood, so that he who was destroying the firstborn would not touch them.

to a festal gathering and assembly of firstborn sons who were enrolled in the heavens, and to God, a Judge of all, and to spirits of righteous men who were made fully perfect,