To God the Father “is attributed the beginning of activity, and the fountain and wellspring of all things”. In relation to Jesus Christ, the Son of God, and in relation to us united with his Son, “Father is the proper name for God, and does not merely describe what he is like”. As John the Apostle records, in the words of the Lord, it is eternal life to know the Father, “the only true God”, and Jesus Christ whom he has sent. To see how this confession of faith in “the God and Father of our Lord, Jesus Christ” necessarily implies Trinitarianism requires fuller explanation from Scripture, and the wisdom which is given by the Holy Spirit.
Father as beginning
The Father created all things by His Word and Spirit; it is from Him that His Son Jesus Christ came “for us and for our salvation” (as the Nicene Creed puts it) in the power of the Holy Spirit; and, it is from Him that the Spirit of His Son is sent into our hearts, crying out to God, “Abba! Father!” Therefore, “in respect to order and degree, the beginning [principium or origo] of divinity is in the Father” It is the Father, in love and for our salvation, who exalted Jesus Christ “far above all rule and authority and power and dominion, and above every name that is named, not only in this age but also in the one to come”. It is the Father who subjects all things to His Son, and “gave him as head over all things to the church”. It is in this sense that the Father is sometimes referred to as the “first person” of the Holy Trinity — but this terminology of “first” (and “second”, and “third”) is for convenience only. It is not meant to imply that there ever has been any God except the Father, Son and Holy Spirit. Neither does it imply that the Son or the Spirit, considered as it were in themselves, are subtractable in any way or in any sense at all. And finally, the Father confessed as the “beginning” of God does not deny that, each one of these distinct Holy Persons is the entirety of God, in every sense except the eternal distinction of persons (see Perichoresis).
Besides being the creator and nurturer of creation by His Son and Spirit, and the provider for his people as revealed in the Old Testament, the New Testament presents God the Father in eternal relation to his only Son, Jesus, which implies an exclusive and intimate familiarity that is of their very nature: “No one knows the Son except the Father, and no one knows the Father except the Son and any one to whom the Son chooses to reveal him.” (Matthew 11:27). In Christian theology, this is the revelation that Fatherhood is inherent to God’s very being. Thus, in Christianity, God is not called Father by comparison to mankind; rather family and fatherhood among men is called such by comparison to God.
An eternal life: sons to the Father
Although God may be said to be Father of all in the sense that he is the Creator of all, the special personal relationship as father is more restricted. God was the father of the nation Israel in the Old Testament in that he chose to set his love on them and set them apart from other nations and peoples. God is the father of Christians in the sense that they are set apart by his sovereign election and indwelt with his Spirit. Thus, Christians are called children of God (cf. John 1:12) in a sense which does not apply to all people.
Christians are made participants in the eternal relationship of Father and Son, through Jesus Christ. Christians are adopted children of God:
“But when the fullness of the time had come, God sent forth His Son, born of a woman, born under the law, to redeem those who were under the law, that we might receive the adoption as sons. And because you are sons, God has sent forth the Spirit of His Son into your hearts crying out, ‘Abba, Father!’ Therefore you are no longer a slave but a son, and if a son, then an heir of God through Christ.” (Galatians 4:4-7)
Worship: to the glory of God the Father
In his Commentary on John, Cyril of Alexandria states, “all things proceed from the Father, but wholly through the Son in the Spirit.” Thus, Christian worship, the fruit of salvation, is a work of God enacted by the Father, accomplished by the Son, and produced by the Holy Spirit. Therefore, Christian worship is a communion with the Father which consists “in his communication of himself unto us, with our returnal unto him” and it flows “from that union which in Jesus Christ we have with him”. The Father is both, the origin and the object of our worship of God through Jesus Christ and in the Holy Spirit. When the Father is in this way the object of worship, the Son and Spirit are not diminished, but properly glorified together with the Father as one God; for the fullness of the Father and of the Son dwells in the one Spirit given to us. Therefore, when we by humbling ourselves in the Holy Spirit glorify the name of Jesus Christ, whom the Father has “highly exalted and bestowed on him the name that is above every name”, it is to the infinite glory of God the Father through the Son in the Spirit.