And [Jesus], being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me. — Acts 1:4
The disciples had just been through the best Bible School training you could have. They walked and talked and lived with Jesus for three years. They heard every sermon He preached, they saw every miracle He performed. If anybody was ever qualified to go and make an impact on the world, it was them! Yet Jesus said not to go, not to leave Jerusalem, without the promise of the Father. If they needed the promise to go, to be effective, we still need the promise today. Do not go-–to work–-to the store-–to the event–-anywhere-–without the promise of the Holy Ghost.