Why is Christ's resurrected body not put back in the tomb?
Christ's resurrected body is spiritual, not the corrupt flesh-and-blood body that goes into the grave. The tomb is for the old physical body prone to disease and failure. Resurrection power brings forth a new body fashioned after Christ, and corruption cannot inherit incorruption.
Les teaches that flesh and blood cannot inherit the Kingdom of God, neither doth corruption inherit incorruption. He explains that you do not put a spiritual body such as Christ's resurrected body back in the tomb. What goes into the grave is the old physical body, already corrupt, prone to disease and failures of one sort or another. But when it comes out in resurrection power, it will be a new body, fashioned after Christ's body. Les then directs attention to Ephesians 1:18, Paul's prayer for believers, and expresses his own anticipation of experiencing this in the next life if not this one.