In ancient Israel, as in much of the ancient Near East, the firstborn son inherited his father’s responsibilities as head of the family (Genesis 27), so we read in the Old Testament that he normally received a special – double – inheritance (Deuteronomy 21:17). We see this fact in the stories of the patriarchs, where we also see that being the “firstborn” was a privilege that could sometimes actually be bestowed on a younger son who was not the literal firstborn at all. When we read the stories of the patriarchs Abraham, Isaac, Jacob, and Joseph, we see that “firstborn” privilege was frequently not based on literal birth order, but on selection.
But whether literally firstborn or chosen as such, the holder of the firstborn birthright held a special place in biblical society. After the Passover slaying of the Egyptian firstborn and the Exodus from Egypt, every firstborn Israelite male was dedicated to God’s service. This obligation was later transferred to the Levites (Numbers 8:14-19), but the significance of the special relationship between God and the firstborn continued, as we see in the fact that the nation of Israel as a whole was called God's firstborn (Exodus 4:22-23, Jeremiah 31:9, etc.). This fact signified Israel’s special standing among the nations and also the priestly responsibility of Israel to be a “light” to the Gentile nations around them.
The term “firstborn” can be used metaphorically in the Bible as well as literally. In the symbolic sense the term was often used in ancient Near Eastern cultures (as it still is today) to mean the superlative example of something – whether good or bad. So in the Book of Job “firstborn” is even used of a terrible disease: “It consumes the parts of his skin; the firstborn of death consumes his limbs” (Job 18:13 ESV). But when speaking of people, firstborn may mean the least or the greatest. So in Isaiah we find “The firstborn of the poor will feed, and the needy will lie down in safety” (Isaiah 14:30 NKJV, ESV, etc.); and the Book of Psalms, speaking prophetically of the coming Messiah, states “… I will appoint him to be my firstborn, the most exalted of the kings of the earth” (Psalm 89:27).
Thus, Jesus Christ is called the “firstborn” in the New Testament, and we can see now how this can mean several things. The term applies both to his literal position as firstborn of God: “… when God brings his firstborn into the world, he says, “Let all God’s angels worship him” (Hebrews 1:6); firstborn from the dead: “… the beginning and the firstborn from among the dead” (Colossians 1:18); and the One who is supreme: “The Son is the image of the invisible God, the firstborn over all creation” (Colossians 1:15).
We see, too, how these meanings flow over into the New Testament’s description of Christians as “firstborn.” Our relationship with Christ and our identification with him mean that we too have become firstborn, like the nation of physical Israel, but even more: “For those God foreknew he also predestined to be conformed to the image of his Son, that he might be the firstborn among many brothers and sisters” (Romans 8:29). That is why the Book of Hebrews refers to Christians as “the church of the firstborn” (Hebrews 12:23).
So, the term “firstborn” in the Scriptures can mean much more than simply “the one born first.” It may mean that, but it may also mean the one to whom the birthright and responsibility was passed (which may apply in many situations, such as what Paul tells us about Christ being the “last” or “second” Adam in 1 Corinthians 15:44-46). “Firstborn” may also mean the greatest or least of individuals or even things. Above all, “firstborn” can refer to several aspects of the nature and role of Jesus Christ – and our identity with the One who is the ultimate firstborn.