The contention stems from the word "Firstborn". Firstborn (the ancient Greek word prototokos) can describe either:
- Priority in time
- Supremacy in rank
The Greek word prototokos, which is translated as firstborn, can refer
to different things. It could refer either to something or someone
that is first in order of time, such as a firstborn child, or it could
refer to someone who is preeminent in rank. Or it could refer to
someone who was both firstborn and preeminent in rank. It all depends
upon the context. (Blueletterbible)
As Paul used it here, he probably had both ideas in mind, with Jesus
being before all created things and Jesus being of a supremely
different order than all created things. (Enduring Word Commentary)
The term “firstborn” in this context is interpreted not as Jesus being the first created being, but rather as a title of honor and authority, signifying His preeminence over all creation.
First born doesn't have to mean literally "birthed first".
Take for example Revelation 1:5.
and from Jesus Christ, the faithful witness, the firstborn from the
dead, and the ruler over the kings of the earth.
To Him who loved us and washed us from our sins in His own blood,
The psalmist gives a description of David as being the firstborn. The Lord said of him.
Also I will make him My firstborn, The highest of the kings of the
earth. (Psalm 89:27).
The title “firstborn” does not imply that Jesus is inferior to God.
In no way does the title firstborn indicate that Jesus is less
than God. In fact, the ancient Rabbis called Yahweh Himself “Firstborn
of the World” (Rabbi Bechai, cited in Lightfoot). Ancient rabbis used
firstborn as a Messianic title: “God said, As I made Jacob a
first-born (Exodus 4:22), so also will I make king Messiah a
first-born (Psalm 89:27).” (R. Nathan in Shemoth Rabba, cited in
Lightfoot) (Enduring Word Commentary)
Paul’s use of the word carries a comparative or superlative meaning, indicating Christ’s supremacy or preeminence rather than his creation.
“The use of this word does not show what Arius argued: that Paul
regarded Christ as a creature like ‘all creation’… It is rather the
comparative (superlative) force of protos that is used.” (Robertson) (Enduring Word Commentary)
Colossians 1:15 describes Jesus as the “firstborn of all creation,” which can be reconciled with Colossians 1:16 and John 1:3 by understanding “firstborn” as a title of rank and authority, rather than implying that Jesus is a created being.
“all things were created through Him,” indicates Jesus’ involvement in creation. Similarly, John 1:3 says “All things were made through Him, and without Him nothing was made that was made,” reinforcing the idea that Jesus is not part of creation but the means by which everything was created.