For there is one God, and one mediator between God and men, the man Christ Jesus;
For there is one God. God's unity in essence and purpose proves His comprehending all His human children (created in His image) in His offer of grace (cf. the same argument from His unity, Romans 3:30; Galatians 3:20); therefore all are to be prayed for. 'The universality of the dispensation is proved by the unity of the Dispenser' (Ellicott). 1 Timothy 2:4 is proved from 1 Timothy 2:5; 1 Timothy 2:1 from 1 Timothy 2:4. The One God is common to all (Isaiah 45:22; Acts 17:26). The one Mediator is Mediator between God and an all potentially (Romans 3:29; Ephesians 4:5-6; Hebrews 8:6; Hebrews 9:15; Hebrews 12:24). They who have not this one God by the one Mediator have none: literally, a go-between. The Greek order is 'one mediator also between,' etc. While God will have all men to be saved by knowing God and the Mediator, there is a legitimate order in the exercise of that will wherewith men must receive it. All mankind constitute ONE MAN before God (Bengel).
The (not in the Greek) man - rather, "man," generically: not a mere individual man: the Second Head of humanity as Mediator, representing in Himself the whole human race and nature (cf. Romans 5:15; 1 Corinthians 8:6; 2 Corinthians 5:19; Colossians 2:14). His being "man" was necessary to His being a Mediator, sympathizing with us through experimental knowledge of our nature (Isaiah 50:4; Hebrews 2:14; Hebrews 4:15). Even in nature, blessings are conveyed to us from God through the mediation of various agents. The effectual intercession of Moses for Israel (Numbers 14:1-45; Deuteronomy 9:1); Abraham for Abimelech (Genesis 20:7); Job for his friends (Job 42:10), the mediation being PRESCRIBED by God while declaring His purpose of forgiveness-all prefigure the grand mediation for all by the One Mediator. On the other hand, 1 Timothy 3:16 asserts that He was also God.