John 14:1 “Let not your heart be troubled; you believe in God,
believe also in Me."
John 13:1 Now before the Feast of the Passover, when Jesus knew that His hour had come that He should depart from this world to the Father, having loved His own who were in the world, He loved them to the end.
Our Lord Jesus knew that at His death, His disciples' faith would be badly shaken. They saw the crippled walked, the blind saw, the deaf heard, the dead resurrected, etc. They believed Him as the Son of God and expected Him to deliver Israel as their King. They could not accept that God can die. God did not die, but the flesh that God came in must suffer (by His stripes we are healed) and then killed (by His death we are redeemed). The disciples then believed only what they saw for to them 'seeing is believing'. Thus, all His disciples deserted Him and Peter went back to fishing.
You believe in God
John 1:29 The next day John saw Jesus coming toward him, and said, “Behold! The Lamb of God who takes away the sin of the world!"
Our Lord reminded His disciples to believe God for God sent Jesus to be the sacrificial Lamb of God.
John 1:35-36 Again, the next day, John stood with two of his disciples. And looking at Jesus as He walked, he said, “Behold the Lamb of God!”
Your also believe in Me
Mat 16:21 From that time Jesus began to show to His disciples that He must go to Jerusalem, and suffer many things from the elders and chief priests and scribes, and be killed, and be raised the third day.
Our Lord constantly reminded His disciples that as the sacrificial Lamb of God, He must suffer many things and then killed, but on the third day He would resurrect.
Mat 20:18-19 “Behold, we are going up to Jerusalem, and the Son of Man will be betrayed to the chief priests and to the scribes; and they will condemn Him to death, and deliver Him to the Gentiles to mock and to scourge and to crucify. And the third day He will rise again.”
Our Lord was trying to raise their faith level by telling them things to come so that they could believe.
John 20:29 Jesus said to him, “Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed.”
Brethren, we must not be like the heathens (or those without the Comforter or Spirit of truth), who only believe what they see. Let us move to the next level of faith whereby we believe the promises of God in accordance to His words and will.