'First born' in the Bible

And further, when he brought the firstborn into the habitable world, he said, Let all the angels of God worship him.

By faith he established the Passover, and the sprinkling with blood, in order that the Destroying Angel might not touch the firstborn.

to the festal assemblage and church of the firstborn, registered in heaven, to a Judge who is God of all, to the spirits of just men made perfect,