An introduction to this subject looks at who these commissions were given to. There were only eleven apostles that received this commission, but the kingdom required that there be 12. The twelve were required to fill the twelve thrones juding the twelve tribes of Israel.
These commissions bind those to whom they were given to the law of Moses. They endow those to whom they were given with power to perform signs and wonders. They also require that Christ be with them to perform the commission that they were given.