"And you know the way to where I am going."
Thomas, ever faithful, but perhaps over-literal, asks Jesus, "How can we know the way?" For Thomas, like so many of us, is expecting a map, perhaps a formula, to get to Heaven. but if Christ had come to give us a map, he'd be no better than those who sought His demise; He would be less than even the prophets who told of his coming; He would not have needed to die.
For Jesus is not a map, and He brought no formula for salvation. He said He is the way. There is no rule except to look on Him and follow.
Later in this conversation with His disciples, Jesus would tell them, "If you love me, you will keep my commandments." But these are not rules or a path to Heaven. In context, we see that this is what Jesus gives us in order for our relationships to God to grow and bear the fruit of peace and joy.
He does not say, "Do this and you will be saved from fire." He does not promise an end to pain or oppression (as the world sees them). He promises peace and he promises joy. He promises the Holy Spirit who will "teach [us] all things and bring to remembrance all that [Jesus has] said to [us]."
Help me, Lord, to rejoice in my troubles as I look on you and find peace and joy.