What is the significance of the four days that Lazarus was dead before Christ raised him?

He was lying dead in the tomb:-

Joh 11:1 And there was a certain sick one, Lazarus of Bethany, the town of Mary and her sister Martha.

Joh 11:2 (And it was that Mary who anointed the Lord with ointment and wiped His feet with her hair, whose brother Lazarus was sick.)

Joh 11:3 Then his sisters sent to Him, saying, Lord, behold, he whom You love is sick.

Joh 11:11 He said these things; and after that He said to them, Our friend Lazarus sleeps. But I go so that I may awaken him out of sleep.

Joh 11:12 Then His disciples said, Lord, if he sleeps, he will get well.

Joh 11:13 But Jesus spoke of his death, but they thought that He had spoken of taking rest in sleep.

Joh 11:14 Then Jesus said to them plainly, Lazarus is dead.

Joh 11:15 And I am glad for your sakes that I was not there, in order that you may believe. But let us go to him.

Joh 11:16 Then Thomas (he being called Twin) said to his fellow disciples, Let us also go, that we may die with Him.

Joh 11:17 Then when Jesus came, He found him already being held in the tomb four days.

Joh 11:19 And many of the Jews came to Martha and Mary in order to comfort them concerning their brother.

Joh 11:20 Then when Martha heard that Jesus was coming, she met Him. But Mary was sitting in the house.

Joh 11:21 Then Martha said to Jesus, Lord, if You had been here, my brother would not have died.

Joh 11:32 Then when Mary had come where Jesus was, seeing Him, Mary fell down at His feet, saying to Him, Lord, if You had been here, my brother would not have died.

Joh 11:33 Then when He saw her weeping, and also the Jews who came with her weeping, Jesus groaned in the spirit and troubled Himself.

Joh 11:34 And He said, Where have you laid him? They said to Him, Lord, come and see.

Joh 11:35 Jesus wept.

Joh 11:36 Then the Jews said, Behold how He loved him!

Joh 11:37 And some of them said, Was not this Man who opened the eyes of the blind able also to cause that even this one should not have died?

Joh 11:38 Then Jesus, groaning in Himself again, came to the tomb. And it was a cave, and a stone lay upon it.

Joh 11:39 Jesus said, Take away the stone. Martha, the sister of him who died, said to Him, Lord, by this time he stinks. For it is the fourth day.

Joh 11:40 Jesus answered her, Did I not say to you that if you would believe you would see the glory of God?

Joh 11:41 Then they took away the stone where the dead was laid. And Jesus lifted up His eyes and said, Father, I thank You that You have heard Me.

Joh 11:42 And I know that You hear Me always, but because of the people who stand by I said it, so that they may believe that You have sent Me.

Joh 11:43 And saying these things, He cried with a loud voice, Lazarus, Here! Outside!

Joh 11:44 And he who had died came out, bound hand and foot with sheets, and his face was bound with a cloth. Jesus said to them, Untie him and let him go!

Joh 12:1 Then, six days before the Passover, Jesus came to Bethany, where Lazarus was (who had died, whom He raised from the dead).

Joh 12:2 Then they made a supper there for Him. And Martha served, but Lazarus was one of those reclining with Him.

Joh 12:9 Then a great crowd of the Jews learned that He was there. And they did not come for Jesus' sake only, but also that they might see Lazarus, whom He had raised from the dead.

Joh 12:10 But the chief priests consulted that they might put Lazarus to death also,

Joh 12:11 because many of the Jews went away and believed on Jesus because of him.