As important as the events of the Cross are to us as christians, the mission that Jesus was sent to do was not completed that day. It is the third day at the tomb that gave the power for Salvation. If not for that day, we would all be like the disciples on the day after Jesus died on the cross, hiding in a locked room grieving for all that had been lost, having nothing but a dark future ahead. None of the gospels mentions a thing about that second day. It was the darkest day of their lives and none of the disciples wanted to record it. But the third day.... That was a day of Victory! It was not enough for Jesus to take all our sins upon Himself, paying our penalty at the Cross. He must also defeat Death itself and arise victorious from the grave. Only the Son of God could do such a thing and He did it for us.
The 20th chapter of John's gospel account starts very early before the sun has really risen enough to dispel all the shadows of the night. As Mary of Magdala walks quietly and sorrowfully to the tomb of the Messiah, she has no idea of what awaits her there. The other gospels tell us she was not walking alone but with other women who had followed Jesus and that they were discussing how they would move the heavy stone that blocked the entrance to the place where Jesus body was laid. They would find neither stone nor body when they reached that place!
The quiet of the morning is suddenly filled with excitement and sound of running feet as Mary hurries to tell the disciples the news that someone has moved the body of their Lord. Peter and John come running, with John in the lead. He skids to a stop outside the tomb, stoops to look in and sees that the body is indeed missing. Peter arrives and, true to his impetuous nature, plunges headlong into the tomb itself, viewing the empty wrappings and the head cloth neatly rolled to one side. Now they believe that the body of Jesus is missing, but who took it and where remains a mystery. They return to tell the others what they saw. There are other sightings of angels and of Jesus Himself to brighten this day and the news spreads that something wonderful is happening!
Later that evening the disciples, who have locked themselves in a room for fear of the Jews, are discussing all that has happened that day. And suddenly Jesus is in the midst of them. He shows them the holes in His hands and the rip in His side so that they will know that this is His risen body, not a ghost. He has indeed been dead, as evidenced by His death wounds, but He is Alive Again! One disciple is missing from the group however and earns his nickname Doubting Thomas, because he won't believe until he puts his finger into the nail holes and his hand in the wound at Jesus' side.
John tells us of Jesus' second visit 8 days later in which He convinces Thomas that the resurrection was not a hoax but reality. Thomas responds with a reverent "My Lord and my God!" Now, after the horror of losing their beloved teacher, the glorious wonder of His miraculous resurrection finally convinces each of them that truly, truly He is the Son of God!
And that is where you and I enter the story. In verse 29, Jesus tells Thomas that there will come those who will believe even though they have never seen the things these men have seen and He calls us Blessed. And then, in order for us to understand how personal this message is, John adds his two cents. I have written this book, he says, "that you may believe that Jesus is the Christ, the Son of God; and that believing you may have life in His name" (v. 31 NASB) He doesn't say so that "all" may believe, or "many" might believe or so that "future generations" will believe. He addresses this book to YOU!
It is kind of like watching a movie and the narrator suddenly turns to face the camera and says "What do You think is happening here?" We have been following John's narrative of the life of Jesus and now he is telling us that WE are the reason that he wrote it all down in the first place. John wants us to believe, as he does, that Jesus is the sinless sacrifice for our sins, the Savior of our souls, the only begotten Son of God. He wants us to hear again the words that Jesus spoke to Martha in John 11:25 "I am the resurrection, and the life: he that believeth in me, though he were dead, yet shall he live".
John wants us to be able to say in reverence with Thomas "My Lord and My God"!