Ephesians 2:18

For through him we both have an access,
That is, both Jews and Gentiles; the Arabic version reads, "we both factions": being made one, and reconciled unto God, and having the Gospel of peace preached to both, they have through Christ freedom of access and boldness in it:

by one Spirit unto the Father:
they may come to God as the Father of spirits, and of mercies, who has made their souls or spirits, and bestowed his mercies on them in great abundance; and as the Father of Christ, and as their God and Father in Christ: and the rather they should consider him in this relation to them, in order to command in them a reverence and fear of him; to secure a freedom and liberty in their approach to him; and to encourage an holy boldness, and a fiducial confidence in him; and to teach them submission to his will: and their access to him is "through" Christ, who has made peace for them, and atonement for their sins; who has satisfied law and justice, and brought in an everlasting righteousness for them; so that there is nothing lies in their way to hinder them; and besides, he takes them as it were by the hand, and leads them into the presence of his Father, and presents their petitions for them, on whose account they have both audience and acceptance with God: and this access is also "by one Spirit"; the "Holy Spirit", as the Ethiopic version reads; and who is necessary in access to God, as a spirit of adoption, to enable and encourage souls to go to God as a father; and as a spirit of supplication, to teach both how to pray, and for what, as they should; and as a free spirit to give them liberty to speak their minds freely, and pour out their souls to God; and as a spirit of faith to engage them to pray in faith, and with holy boldness, confidence, and importunity; and he is said to be "one", both with respect to the persons to and by whom access is had, the Father and Christ, for he is the one and the same Spirit of the Father and of the Son; and with respect to the persons who have this access, Jews and Gentiles, who as they make up one body, are actuated and directed by, and drink into one and the same Spirit: hence this access to God is of a spiritual kind; it is a drawing nigh to God with the heart, and a worshipping him in spirit; and is by faith, and may be with freedom, and should be, with reverence, and ought to be frequent; and is a peculiar privilege that belongs to the children of God; and who have great honour bestowed upon them, to have access to God at any time, as their Father, through Christ the Mediator, and under the influence, and by the direction and assistance of the Holy Spirit: this is a considerable proof of a trinity of persons in the Godhead, of their deity and distinct personality.