About a month before His own death and resurrection, Jesus visited Bethany and performed His third miracle of resurrection, raising Lazarus from the dead (John 11:1-46). No one knows how often Jesus visited the home of the sisters, Mary and Martha, and their brother Lazarus, but Scripture records some of His visits to their friendly, peaceful, and loving home (Matthew 21:17; Mark 11:11, 19; Luke 10:41-42).
This resurrection is the most extraordinary of all His great works while in the flesh. It foreshadowed His own resurrection, made a profound impression in Jerusalem, and in contrast, brought the wrath of the Sanhedrin to a head, stirring them to decide to murder Jesus. After performing this miracle, He withdrew to the wilderness of Ephraim for some private time with His disciples before the Passover and His final hours.
Martin G. Collins
The Miracles of Jesus Christ: The Resurrection of Lazarus (Part One)
Jesus and Martha were talking on two different levels. She understood in a way, but not what Jesus was really saying. Jesus was talking about a resurrection that would occur in just a few moments, while she meant a resurrection that will occur when God resurrect the firstfruits. They were speaking about the same subject, but their timing was off, so to speak.
John W. Ritenbaugh
Faith and Prayer
Other Forerunner Commentary entries containing John 11:21: