John 14:6 is set within Jesus’ final discussion with his disciples before he is arrested, which began in the upper room in 13:1 and ends with his arrest in chapter 18. Chapter 13 ends with Jesus predicting that Peter will deny him three times, and, (apparently) immediately after this grim word, he says to all the disciples, “Let not your hearts be troubled” (14:1). He says to them basically, “Don’t let all this talk of betrayal, denial, and death shake you up! Just trust me!” But, from the disciples’ perspective, if even Peter will deny Jesus, how can any of the disciples have any hope? Nevertheless, Jesus offers a word of comfort. He commands them to trust God and, especially, to trust him. So that they will be comforted, even with the predicted failure of Peter looming over their heads, he assures them of their future presence with God, and he begins right here to tell them clearly that he is about to leave them. But, he begins telling them this with an edge of hope, because he points out to them that he is leaving to prepare a place for them. He characterizes where he’s going as his Father’s house, a house with many rooms. It seems that he is telling them that he is going to prepare a place for each of his disciples, a room for each disciple in his Father’s house. Thus, heaven is here being depicted as a very intimate place for a family (a house) in which each person has their own personal, unique quarters, that Jesus himself prepares for them. And he tells them that he will come back to fetch them so that they will be with him where he is. They need to be with him; he wants to be with them, and he is going to make it possible. Then, Jesus shifts the conversation slightly by suggesting that the disciples know “the way,” they know how to get where Jesus is going.
At this point, Thomas steps in and objects that they do not have any idea where Jesus is going or how to get there. (It is interesting to me that how a reader understands Thomas’ final appearance in John’s Gospel significantly affects the way he is viewed in each of his other, earlier appearances in the Gospel. Personally, I think Thomas has a bad reputation; I don’t think he should be construed as “Doubting Thomas.” The text might imply that he doubted [John 20:27; though only the NIV among major translations translates the verb “doubt” here, and I think this is unwarranted]; nevertheless, I think Thomas’ words and actions were motivated by his deep love for Jesus and intense grief after his death.) Even up to this point, just before Jesus is betrayed and arrested, the disciples still cannot fathom the reality that Jesus will be executed as a criminal. If we bring in Mark’s account of Jesus’ life, at least 3 times Jesus told them plainly that he would be killed and would rise from the dead (Mark 8:31; 9:31; 10:33-34). But they still don’t get it. But here, Jesus indicates that he is going home, he is going to his proper dwelling, and he is going to make his home their home. In response to Thomas’ honest claim of ignorance, Jesus’ announces that he himself is “the way,” the way to get where he is going. But he goes further. He states, “I am the way, and the truth, and the life.” He very much intends to claim, “I am the only way; I am the only truth; I am the only life.” Thus, Jesus binds together 3 very important concepts, but I think it is important to let the lead concept (“the way”) drive the meaning of the whole statement, since that is the specific connection to Thomas’ question.
The concepts of “truth” and “life” are major themes of John’s Gospel, but “the way” is introduced only here by Jesus. However, the term does occur in John 1:23, quoting Isa. 40:3, referring, significantly, to Isaiah’s “way of Yahweh” and how John the Baptist is the “voice” who cuts the path for Yahweh’s coming. Interestingly, Isa. 40:3 is quoted in all 4 Gospels to refer to John the Baptist; for an OT text to appear in the same way in all 4 Gospels is incredibly rare. I digress…. I can probably do no better here than to quote Carson, whose commentary on John is, I repeat, superb: “Jesus is the way to God, precisely because he is the truth of God…and the life of God….Jesus is the truth, because he embodies the supreme revelation of God—he himself ‘narrates’ God (1:18), says and does exclusively what the Father gives him to say and do (5:19ff; 8:29), indeed he is properly called ‘God’ (1:1, 18; 20:28). He is God’s gracious self-disclosure, his ‘Word,’ made flesh (1:14). Jesus is the life (1:4), the one who has ‘life in himself’ (5:26), ‘the resurrection and the life’ (11:25), ‘the true God and eternal life’ (1 Jn. 5:20). Only because he is the truth and the life can Jesus be the way for others to come to God, the way for his disciples to attain the many dwelling-places in the Father’s house (vv. 2-3), and therefore the answer to Thomas’ question (v. 5).” The most fundamental truth of all reality is the truth about God, who he is and what he’s done in history. Who God is can most clearly be seen in Jesus, and what God has done in history can only be understood rightly in Jesus.
Emphasizing Jesus’ exclusive claim here is important, mostly, because Jesus emphasizes it so strongly himself. He adds, in case the disciples didn’t quite get what he meant, “No one comes to the Father except through me.” Thomas’ question is, “How can we get where you’re going?” Jesus has said that he is going home to his Father. How do we get to the Father? Only through Jesus. There is no other way. If you leave off the “except through me” statement, what do you have left? “No one comes to the Father.” Period. This is the negative side of God’s gracious initiative. Jesus could have stated it just like this as a description of reality. No one comes to the Father. On our own, left to ourselves, no one comes to the Father. We are rebels. However, in God’s own amazing grace, God provides a way for sinners to come to the Father. And it’s Jesus.
Sinful people don’t deserve to live with God. God has freely, graciously, and lovingly provided one pathway, one avenue, one road to travel that leads home, living forever in a healthy relationship with God. That one way is trusting in Jesus as the only one who shows us what God is actually like and trusting in Jesus as the only one who has done what is necessary for sinful people to live with God. Namely, Jesus lived the life that you and I are expected to live before God, that is, a life of obedience and worship of the one true God. He never sinned. People who sin deserve to die, according to God’s law and because of God’s good and just character. Jesus is the only human being who never sinned. Thus, he is the only person who has ever lived who did not deserve to die. But, he chose to give up his life—to die—to pay the penalty for the sins of other people. He did not earn the cross that he bore. We did. I did. You did. But God has provided this way, and only this way, for us to avoid the death we deserve and to live a full, rich, eternal life that pleases God. Jesus died the death we deserve, but he rose from the dead on the third day, totally victorious over death and sin. No other religious teacher, no other guru, no other human being, no other self-help course, no other gospel can provide full access to God. There is no other name in this world by which people may be saved (Acts 4:12). Only Jesus. Without Jesus, every single one of us is utterly lost, totally without God and without hope. But the double-edged promise is extended to all, and it is a sure promise: “Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him” (John 3:36). You want life with God, now and forever? Trust Jesus! He is the only way to the Father. And may we worship God and thank him always for providing a way at all to sinners like us. We don’t deserve access to this utterly good, utterly loving, utterly holy God, but, in his great mercy, he chose to make a way. Yes, “the gate is narrow and the way is hard that leads to life, and those who find it are few” (Matt. 7:13), but there is a gate, there is a way, and that gate is Jesus; that way is Jesus. So, enter by the narrow gate; begin trusting in Jesus today. God has made known to you, today, the path to eternal life with him, and in his presence there is fullness of joy, pleasures forevermore (Ps. 16:11). Embrace Jesus! Trust Jesus!
 D.A. Carson. The Gospel According to John. Pillar New Testament Commentary. Grand Rapids: Eerdmans, 1991. 491.