Let us begin by explaining the key terms in this verse.
There is one God:
There is only one true God, the Creator of all things. All other so-called gods are idols made by human hands. As Scripture says, “For all the gods of the people are idols: but the LORD made the heavens” (1 Chronicles 16:26).
One mediator between God and men:
A mediator is someone who stands between two parties in order to bring them together. Humanity is separated from God because of sin, and therefore we need a mediator to reconcile us to Him.
The man Christ Jesus:
The Lord Jesus Christ is both fully God and fully man. He is truly human, so He can represent us, and He is the Son of God, sent by the Father, so He can speak for God and fully satisfy God’s holiness and justice.
Who gave Himself a ransom for all:
A ransom is a price paid to set someone free. The Lord Jesus Christ gave His life to free people from sin and death. This redemption is received through faith in Him and in His finished work. He gave Himself for all, not merely for a select few, though sadly many reject this gracious gift of divine love.
To be testified in due time:
This message was revealed at the appointed time in history and is now being proclaimed. As Scripture declares, “But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law, to redeem them that were under the law, that we might receive the adoption of sons” (Galatians 4:4–5).
The Lord Jesus Christ alone brings people to God, because He alone gave His life as a ransom for sinners. Seeking forgiveness or reconciliation through any other person, system, or work is futile, for salvation is found only in Him.