How does the three days and three nights show that Jesus really died?
The three days and three nights in the tomb prove that Christ's death was genuine, not merely an unconscious state or a trick. The duration demonstrates He was truly dead, so the resurrection is from real death. That same reality applies to believers, whose old Adam must truly die and be buried with Him.
Les explains that Christ was really dead, and the three days and three nights in the tomb were given to prove it was not just an unconscious state. He did not merely put on a Houdini-like escape. The same pattern applies to believers: old Adam has to die, and as Christ died and was buried, we died and were buried in the mind of Christ, the mind of God. Just as He did not stay in the tomb, we are resurrected out of it. This baptism into death goes beyond what water baptism can do.