John's Gospel is unique in that it is a theological presentation of Christ and His work that does not use the Synoptics as a foundation. John's purpose is "so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in His name" (20:21). John's Gospel has many layers to it. He frames Jesus' ministry by using the three sacraments that represent the three aspects of salvation in the order in which they occur to believers: baptism that represents regeneration/justification, communion that represents sanctification via the cross, and marriage that represents glorification/consummation. Throughout all of them, the word/truth and the Spirit as the means of creation play a prominent role in terms of what makes up the teaching of the book.
Theology: Jesus is God the Son who has become incarnate in order to make God known (1:14, 18). Knowing God and Jesus Christ is eternal life itself (17:3), so the goal of the incarnation is salvation via knowing God (17:25-26). John uses language from Genesis 1 in his prologue because he wishes to argue that Jesus is the means through which God creates life. The Son is called the
logos "word" because John wishes to present Him, His work, and His teaching, as the means by which God creates the world and His people. It is through the Person of the Son, the work of the Son, and the words of the Son that God draws His people who He causes to be born again and to be given life. The Spirit applies the word, as He does in creation, and brings about light and life. So the picture emerges that the Father initiates by giving the Word, and the Word is applied by the Spirit to an individual who is then brought to life by this divine activity. Hence, there is a Trinitarian fellowship that brings about the salvation of God's people by regenerating, sanctifying, and resurrecting them to eternal fellowship with the Triune God, which is why Jesus states in the Gospel, "This is the work of God: that you believe in the One He has sent" (6:29).
There is no distinction between God's word and the Word, as it has often been said. In fact, the entire point is that the Logos/Word is expressed in both His words and those in the Old Testament, so that to abide in Him is to abide in His words (15:7). All of the Old Testament Scripture speaks of the Son (5:37-40) and the Son's words are the Father's words that reflect the mind and Person of the Father (3:34; 8:26-28). There is, therefore, no separation of God, His work, and His words. To believe in God is to believe in Him, His work and His words all together.
Jesus is one with the God of the Old Testament (John 1:1; 10:30). His Father is the God of the Old Testament, as evidenced by His confirmation of the Old Testament, Moses, Abraham, and their God being the true God throughout the Gospel. He is YHWH of the Old Testament (8:58-59). This is an important point that John is making because the Gnostics denied that the God of the Old Testament was the Father of the Son. They would prefer a different God than that of the Old Testament be the Father of the Son, and that the Son break from the Old Testament rather than affirm it as He does (7:19; 10:35). John states that there is only one true God (17:3), and the Father, Son, and Holy Spirit are that one God (1:1; 5:18; 10:30-33; 15:26).
God chooses some but not others to give to the Son (6:44; 10:26-27). Those who do not come to Him do not do so because they are not drawn by the Father, and therefore, do not belong to the Son. Hence, Jesus only prays for those who the Father gives Him, but not for the rest of the world (17:9).
The world in John both represents the whole pool from which His people are drawn and the wicked world in rebellion toward God. It does not always mean everyone in the world, but rather that His people are made up from every part of the world, otherwise, a great contradiction exists between texts like John 3:16 and John 17:9. The understanding of world in a general, but not specific and unlimited sense, is consistent with Johannine theology in general. God's people are not the world, but they represent the world in that they are drawn from every nation, tribe, and language group.
Hence, the word "life," along with "light/word/words/truth" and "Spirit" are presented throughout the Gospel because John wishes to argue that only in Jesus, His work, and His words does God bring anyone to life. In Him, there is life. Outside of Him, there is nothing but wrath, darkness, and death.
At the center of this word is the gospel of Jesus Christ, who draws all to Himself by being lifted up (12:32-33) and will bring healing to all who trust in His work (3:14-17). Likewise, the resurrection plays a prominent role in the Gospel as that which is found only through the Word/Christ as the one who is resurrected from the dead, and therefore, identified as the resurrection itself (11:25; 14:19), given to all who are given by the Father to Him and therefore come to Him (6:37-40, 44-47).
The Word/word is used to shed light on every person by the Holy Spirit, who is called the Spirit of Truth. With Christ's words, He convicts the world concerning its sin and error. Those who wish to remain in sin do so because they love the darkness/the lies of the wicked world, rather than the light/the truth of God because lies give them the ability to live in sin (3:19-21).
What emerges in John, therefore, is a theology of fellowship with the Triune God and love of His people through the worship of Spirit and truth that then gives life to all who abide in the Son and His words.
Ethics: Since it is only through the Son's work and words that God the Father brings His people to life, it is only those who remain united to His Son via believing/obeying Him that this salvation will be applied by the Spirit (15:1-7). This also means that those who shepherd Christ's sheep must do the work of ministry by feeding them word and sacrament (21:15-17), which is the food and drink that satisfies forever (4:13-14, 31-34; 6:30-35). It also means that only those who abide in Christ and His word will bear much fruit (15:2, 4, 8).
Hence, to worship God is to worship Him through the Spirit and truth,
since this is the means by which He creates life in His people (4:24).
Since it is the Son who the Father loves, it is those who obey the Son who the Father loves (3:35-36; 5:20; 14:23; 17:22-24). Hence, anyone He loves He draws and unites them to the Son (6:37-40; 44-47; 17:6, 9). Federal headship is strongly at play in the Gospel. God gives life to those in the Son because that is the Son's reward, but the wrath of God abides on everyone else (3:36). If one, therefore, believes, it is because God has designated him to be His, is drawing him, and has caused him to be born again/raised to a life that creates more life, a life of creational activity as the fruit of being in Christ/the Word and enlivened by the Spirit (7:38-39). John wishes to argue, then, that those born of God are not born by anyone else's will, but God's. Not even their own will has led them to being adopted as sons in the Son.
The fruit is obedience to Christ's commands in loving God and fellow Christians in the truth. It is this love for one another that identifies Christians as Christ's disciples (13:34-35; 15:12, 17. Hence, the Father loves the Son, and therefore, all who are in the Son, so to love the Son is to love those who are in the Son as well. Hence, Christians are to love other Christians who are in the Son as evidence that they love the Son and prove that they are, therefore, the disciples of the Son.