Behold, I send the promise, &c.— That is, I will shortly send; the present being used for the future tense, as it is frequently in scripture. Till ye be endued, or invested with power from on high, means, "Till you are inspired with the Holy Ghost from above."
Related Commentaries of Luke 24:49
Luke 24:49
49 And, behold, I send the promise of my Father upon you: but tarry ye in the city of Jerusalem, until ye be endued with power from on high.