The word “firstborn” (prōtotokos) refers to more than just one thing in the New Testament. Here are the nine passages where it occurs.
Of Firstborn Children
Matthew 1:25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.
Refers to a son who is the first son born to a woman.
Luke 2:7 And she brought forth her firstborn son, and wrapped him in swaddling clothes, and laid him in a manger; because there was no room for them in the inn.
Same as the verse above.
Hebrews 11:28 Through faith he [Moses] kept the passover, and the sprinkling of blood, lest he that destroyed the firstborn should touch them.
This is a reference to the firstborn among human and cattle alike in Egypt at the Exodus.
Of Christ as the Firstborn of Every Creature
Colossians 1:15 Who [Jesus] is the image of the invisible God, the firstborn of every creature:
This seems to be a reference to Jesus having existed before anything in the creation was made. The particulars of it are debatable.
Hebrews 1:6 And again, when he bringeth in the firstbegotten (same word in the Greek: prōtotokos) into the world, he saith, And let all the angels of God worship him.
This usage seems to be intended in the same way as Colossians 1:15 above, to refer to Jesus as “the firstborn of every creature”. It probably also references his birth into a human body in Bethlehem, as many angels worshiped him there:
Luke 2:13 And suddenly there was with the angel a multitude of the heavenly host praising God and saying, 14 “Glory to God in the highest, and on earth peace among those with whom he is pleased!”
Of Christ as the Firstborn from the Dead
Colossians 1:18 And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence.
Jesus was the first person to rise from Sheol/Hades. He was not literally “born” out of Sheol/Hades. Rather, this is a metaphor, likening his escape to a birth. This is to be distinguished from other deaths (such as Lazarus’, for example), where the spirit did not enter Sheol/Hades. (See 2 Esdras 7:75-101) And in case you’re wondering, we do know that Jesus’ spirit descended to Hades/Sheol. Read about it here.
Revelation 1:5 And from Jesus Christ, who is the faithful witness, and the first begotten of the dead, and the prince of the kings of the earth. Unto him that loved us, and washed us from our sins in his own blood,
Again, Jesus is referred to in his role as the first to be raised from the dead in Sheol/Hades.
Romans 8:29 For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren. 30 And those whom he predestined he also called, and those whom he called he also justified, and those whom he justified he also glorified.
This one’s more difficult, and my interpretation of it will surely be controversial. This is also a mention of Christ as the firstborn from among the dead, yet were we have “many brethren” introduced into the conversation. Those God “forenew” are those whom God “knew before”. This is not a reference to God’s all-knowing nature, but to history. God determined that people he had previously known would be conformed to be raised like Jesus from Hades/Sheol and given a body like his. Note that these people had already been known by God, predestined to be made like Jesus, called, justified, and glorified. This was not Paul telling them about their own future directly, but about the recent past where these people had been raised in Matthew 27:52-53. Paul’s message to the Romans was that if THESE people had been raised as promised, that God would certainly not forget the Romans.
Jesus was made the “firstborn” among “many brethren” when he raised up those others right after he himself was raised.
Hebrews 12:23 To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect,
Here the word prōtotokos appears in the plural. Here it is in the Greek for those who’d like to see it:
12:23 πανηγύρει καὶ ἐκκλησίᾳ πρωτοτόκων ἐν οὐρανοῖς ἀπογεγραμμένων καὶ κριτῇ θεῷ πάντων καὶ πνεύμασιν δικαίων τετελειωμένων