It must have shocked Jesus to hear Thomas say, "Lord, we know not whither thou goest; and how can we know the way?" (John 14:5). Thomas was really saying, "Jesus, You speak so intimately about going to Your Father, but we don't know Him as You do. How can we know the way to the Father?"
This was a confession. Thomas was admitting, "Lord, we know You. We've been intimate with You for the past three years, but we have no revelation of who the Father is — of His love, His care, His tenderness. Please, before You go, show us the Father." Yet, that is just what Jesus had been doing for the past three years. His disciples had missed the revelation.
If we fully understand that we have a loving, caring heavenly Father, why would we ever be downcast when the enemy comes against us? Why would we despair over a financial burden that seems overwhelming? Why would we wonder why we cannot seem to get victory over a besetting sin?
Listen carefully to Jesus' answer to Thomas. It has everything to do with us: "If ye had known me, ye should have known my Father also" (John 14: 7).
Then Philip speaks up: "Lord, shew us the Father, and it sufficeth us" (verse 8). Jesus could not believe what He was hearing. You can almost hear the incredulity in His voice as He answers Philip: "Have I been so long time with you, and yet hast thou not known me, Philip? He that hath seen me hath seen the Father; and how sayest thou then, Shew us the Father?" (verse 9).
In other words: "Thomas, Philip, my precious disciples, how can you ask this? You say you know Me, that we are intimate. Yet how could you miss the revelation I have spent the past three years giving you? Don't you yet see that all the mighty works I did were the Father in Me revealing who He is, what He is like, what He wants to be to you? All I taught you was from His heart, not Mine."
Jesus' whole life was an illustrated sermon. Day by day, with every miracle He performed and every parable He taught, He was expressing who the Father is. And He sent His Holy Spirit so His followers could do even greater works and keep revealing the Father's love to new generations.