Jesus Christ was concerned that as a result of the challenges faced in this life, His disciples would take their eyes off Him and stumble by not follow His life-giving law. That was the same concern Christ had for the Children of Israel as they exited Egypt.  In John 15, Jesus Christ gave to the apostles and therefore the disciples, which includes us in this day and age, four instructions at the foundation of what we should be focusing on after the Passover and Days of Unleavened Bread, to make sure we do not stumble.