11 The former account, indeed, I made concerning all things, O Theophilus, that Jesus began both to do and to teach, 2 till the day in which, having given command, through the Holy Spirit, to the apostles whom he did choose out, he was taken up, 3 to whom also he did present himself alive after his suffering, in many certain proofs, through forty days being seen by them, and speaking the things concerning the reign of God. 4 And being assembled together with them, he commanded them not to depart from Jerusalem, but to wait for the promise of the Father, which, 'saith he,' 'Ye did hear of me; 5 because John, indeed, baptized with water, and ye shall be baptized with the Holy Spirit—after not many days.'
Matthew Henry's Commentary on Acts 1:1-5
Commentary on Acts 1:1-5
(Read Acts 1:1-5)
Our Lord told the disciples the work they were to do. The apostles met together at Jerusalem; Christ having ordered them not to depart thence, but to wait for the pouring out of the Holy Spirit. This would be a baptism by the Holy Ghost, giving them power to work miracles, and enlightening and sanctifying their souls. This confirms the Divine promise, and encourages us to depend upon it, that we have heard it from Christ; for in Him all the promises of God are yea and amen.