1 Timothy 2:5

For there is one God
This does not so much regard the unity of God, with respect to himself, or his divine essence, though that is a truth; but does not carry in it any apparent and forcible reason why all men should be prayed for, for which it is produced; but the unity of God with respect to men, as that there is but one God, who is the Creator of all men, and who, in a providential way, is the Saviour of all men; and in a way of special grace is the one God, the one covenant God of all sorts of men, of Jews and Gentiles; for he has taken of the latter into the covenant of his grace, as well as the former, and has loved them with a special and distinguishing love, has chosen them in Christ to salvation, and has sent his Son to redeem them; and of these he calls by his grace, regenerates, sanctifies, adopts, pardons, and justifies; see ( Romans 3:29 Romans 3:30 ) and therefore all sorts of men, Gentiles as well as Jews, are to be prayed for: another argument follows,

and one Mediator between God and men;
a Mediator is of more than one, and has to do with two parties; and these at variance among themselves, between whom he stands as a middle person; his business is to bring them together, and make peace between them; and such an one is Christ: the two parties are God and his elect, who in their natural state are at a distance from God, and at enmity to him, and who have broken his law, and affronted his justice; Christ stands as a middle person, a daysman between them, and lays his hands upon them both; has to do with things pertaining to the glory of God, and makes reconciliation for the sins of the people; brings them that were afar off nigh to God, and makes peace for them by the blood of his cross, by fulfilling the law, and satisfying justice for them; in consequence of this he appears for them in the court of heaven, intercedes and pleads for them, is their advocate, and sees that all covenant blessings, of which he is the Mediator, are applied unto them, and preserves their persons, which are committed to his care and charge, safe to everlasting happiness; and this Mediator is

the man Christ Jesus;
not that he is a mere man, for he is truly and properly God; or that he is a Mediator only according to the human nature: it was proper indeed that he should be man, that he might have something to offer, and that he might be capable of obeying, suffering, and dying, and so of making satisfaction in the nature that had sinned; but then, had he not been God, he could not have drawn nigh to God on the behalf of men, and undertook for them, and much less have performed; nor would his blood, righteousness, and sacrifice, have been available to cleanse from sin, to procure the pardon of it, justify from it, make atonement for it, or make peace with God: the reason why he is particularly mentioned as man, is, with a view to the argument in hand, praying for all men; since he who is the Mediator between God and man, has assumed a nature which is common to them all: and this Mediator is said to be one, not so much in opposition to other mediators, angels or saints departed, though it is a truth, and stands full against them, but with respect to men; there is but one Mediator between God and all sorts of men, through whom both Jews and Gentiles have an access to God, and peace with him; and therefore prayer through this Mediator should be made for all. So the Jews say of the Messiah ^F21, that he is (yeuma la) , "a Mediator, God", a middle person between God and men. And they call him (atyeumad adwme) , "the Pillar of mediation" ^F23 or the middle Pillar; that is, the Mediator or Reconciler. And Philo ^F24 the Jew speaks of the word, as (mesov) , a "middle" person, and standing in the middle between the dead and the living, and between God and men. The Ethiopic version here renders it, "there is one elect of God"; which is one of the characters of the Messiah, ( Isaiah 42:1 ) .