"You know where I am going, and you know the way. 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, the truth, and the life ; No one comes to the Father except by me." John 14. 4-6
In the upper room, the Lord announces to his disciples that he will leave them to prepare a place for them in the house of his Father. This is something so new to them that they can not understand its meaning. They know Moses and the prophets, but they did not speak of God as a Father. That is why Thomas exposes their ignorance to the Lord : since they do not know God as Father, they can not know the path that leads to Him.
It is Jesus, his only Son, who can reveal God to us as Father. He is the only way in which God manifests his love for mankind. It is a love so great that it will lead Jesus to bear our sins on the cross and die in our place. To go to God there is no other way than to repent and accept the love of God who, in Jesus Christ, provided for the salvation of men.
From the moment he takes this path, a sinner is saved from eternal perdition. Better, he can know God as Father, for he receives "the Spirit of adoption, by which we cry : Abba, Father !" (Rom. He can feel the love that flows from this filial relationship with God, become his Father in Jesus. In all the circumstances he passes through, the child of God can turn to this gracious Father, confide his problems and receive answers.
Soon he will be introduced into the abodes of the Father's house, he will taste the full extent of this divine love and measure the price paid by the Lord to reveal it to him. Indeed, we will remember the journey that the Lord had to make to become himself the way to the Father's house. He left her, this abode of love, the only begotten Son, to come and suffer on earth; He even descended "into the lower parts of the earth". But, glory to God, he ascended "above all the heavens" (Ephesians 4: 9, 10), whence he comes to seek us.
Source (To pleasing the Lord)