In the last chapter Jesus make it clear that one of them would betray Him, that He was going to leave them and that Peter would soon deny Him. Now He will give them several reasons for their hearts to be at peace.
First, He was going to come back to take them to a place He would prepare. In the meantime, they would enjoy the presence of another Helper like Him, through whom He would actually be present in a different way – within them. They would also enjoy a new privilege – praying in His name.
In John 14:6 Jesus also makes it clear that He is the only way to the Father, or the only way to God.
No one gets to God by any other means except through Jesus, but each one who comes to Jesus receives many undeserved blessings.