Having faith in a printer that won't print won't make it print. Having faith in a light switch when there's no electricity won't make the light turn on. Having faith in a truck with a broken engine won't make the truck run. The same holds true of our salvation. If we put our faith in an object that cannot save us, we won't be saved.
The most important question in all human history addresses this issue. In Matthew 16:15, Jesus asked, "Who do you say that I am?"
Just before he died, church historian Jaroslav Pelikan said, "If Christ is raised, nothing else matters. If Christ is not raised, nothing matters." 
Jesus made a number of claims about Himself in John 14.
Verse 1 says, "Let not your hearts be troubled. Believe in God; believe also in me."
Alexander Maclaren wrote that, when Jesus said, "Believe in Me," "He was either a wrong, crazy enthusiast who was insane—or—He was 'God manifest in the flesh.'" 
Jesus went on to affirm that, because they saw Him, they saw the Father. If we're going to have faith in the Father, we must have faith in Christ. We can trust Him when things are going well and
when our circumstances become overwhelming. Nothing is too difficult for Him, and nothing can jeopardize His sovereignty (Jeremiah 32:17; Job 42:2).
Verses 4-6 read this way: "'And you know the way to where I am going.' Thomas said to him, 'Lord, we do not know where you are going. How can we know the way?' Jesus said to him, 'I am the way, and the truth, and the life. No one comes to the Father except through me.'"
Jesus claimed to be worthy of our faith and trust. He also claimed that having faith in Him would provide comfort.
Thankfully, the disciples often asked clarifying questions. And in response to Thomas's question here, Jesus didn't say He would show them the way to heaven. He said He was the Way!
Jesus is saying there isn't anything we can do in our own power, in our own ability, in our own strength to find our way to heaven. The only way anyone can get there is to follow Jesus.
Jesus also claimed to the Truth. He's saying He is dependable in all things and the only source of truth. The only way anyone can know what life is really like is to know the truth, and the only way to do that is to know Jesus as Savior and Lord.
Jesus also claimed to be the Life. Jesus doesn't show us the way; He doesn't point us to the truth, and He doesn't reveal the source of life. The moment we're conceived, we're under the curse of sin, separated from the holy God. Because of sin, we deserve God's wrath. The only way anyone can have life is through Jesus. The only way anyone can have life is knowing the only true God and Jesus Christ, whom He sent (John 17:3).
When Leon Morris was reading this text and contemplated Jesus calling Himself the way, the truth, and the life, he said this:
- "'Way,' 'truth,' and 'life' all have relevance, the triple expression emphasizing the many-sidedness of the saving work. 'Way' speaks of a connection between two persons or things, and here a link between God and sinners. Jesus is saying the only way anyone can have a connection to God the Father is through Him. 'Truth' reminds us of the complete reliability of Jesus in all that he does and is. Everything Jesus has said about Himself, and His promises to His people are not only true, but absolutely trustworthy, without hesitation or reservation. And 'life' stresses the fact that mere physical existence matters little. The only life worth living is that which Jesus brings, for he is life itself." 
He goes on to say that we need to remember when and where Jesus made these statements. He didn't make them while sitting on a throne or at the height of His ministry. He didn't make them when everything was easy. Jesus spoke these words on the eve of His crucifixion.
Jesus knew what was coming, but He also knew what was coming for all who would believe in Him. He knew there would be times of trouble that would shake us to our core. So, how does Jesus claiming to be the way, the truth, and the life, provide us comfort? We have access to the Father through Him. Through Jesus we can take all our sorrow, pain, grief, questions, issues, frustrations, and uncertainties into the presence of the God who spoke the universe into existence.
In John 1:18, Jesus said, "No one has ever seen God; the only God, who is at the Father's side, he has made him known."
To know Jesus is to know the Father. He is the only One who can reveal the Father to us. This comment prompts Philip to ask in verse 8, "Lord, show us the Father, and it is enough for us."
None of the disciples understood that God was sitting right in front of them.
Verse 9 seems to be a gentle rebuke. "Have I been with you so long, and you still do not know me, Philip? Whoever has seen me has seen the Father. How can you say, 'Show us the Father'?"
It's so simple and straightforward, and that's what makes it powerful. If you've seen Jesus, you've seen God.
That's why Jesus continues in verses 10-11: "Do you not believe that I am in the Father and the Father is in me? The words that I say to you I do not speak on my own authority, but the Father who dwells in me does his works. Believe me that I am in the Father and the Father is in me, or else believe on account of the works themselves."
This brings us back full circle to verse 1. To believe in Jesus is to believe in the Father because the two are inseparable. To know Jesus is to know God. He calls His disciples to examine His teaching and His lifestyle in order to believe that seeing Him is the same as seeing the Father.
Even today, we struggle to grasp this truth. But if we don't look at Christ and see the glory of God, then we haven't truly seen Christ. If we want to know what God is like, we are to look into the face of Jesus Christ. If we look deeply into His words and His works, we'll see the Father.
Notice that Jesus challenges us in verse 11 to "believe Me that …"
Jesus is challenging us to believe that
He deserves equal faith with God, that
He's the only way to God, that
He's the revealer of God, and that
He's one with the Father.
If we struggle to believe His words, we can believe His works. Believing in the person of Christ will comfort our troubled heart because He is God in flesh.
Jesus's promises in verses 2 and 3 give us hope in times of trouble. "In my Father's house are many rooms. If it were not so, would I have told you that I go to prepare a place for you? And if I go and prepare a place for you, I will come again and will take you to myself, that where I am you may be also."
 Cited by David Calhoun, in Heaven [Crossway], ed. by Christopher Morgan and Robert Peterson, worldmag.com/2014/11/the_hope_of_heaven.
 Expositions of Holy Scripture [Baker], on John 14:1, p. 257
 Leon Morris, The Gospel According to John [Eerdmans], p. 641