(27) And ye also shall bear witness.--The tense is present, and ye also bear witness; or, and ye also are witnesses. (Comp. Notes on Luke 24:48-49.) The Apostles themselves distinguished between their own witness of things which had come within their own experience and the witness borne by the power of the Holy Spirit, of which the Day of Pentecost was the first great instance. (Comp. Acts 5:32.)

Because ye have been with me from the beginning.--Comp. John 1:7; and Notes on Acts 1:21-22. The "beginning" of course means the beginning of the Messianic teaching and works of which they were to be witnesses.

15:26,27. The blessed Spirit will maintain the cause of Christ in the world, notwithstanding the opposition it meets with. Believers taught and encouraged by his influences, would bear testimony to Christ and his salvation.And ye shall also bear witness,.... That is, of Christ; of all the things he did in Jerusalem, and in the land of the Jews; being eyewitnesses, and ministers, or servants of the word, who constantly attended upon him; of all the good he did to the bodies and souls of men; of the various miracles he wrought, and of the several doctrines which were taught by him: what they saw with their eyes, heard with their ears, and with their hands handled of the word of life, that they could declare, and did declare, and bore a faithful testimony to; they were to be, and were witnesses of his sufferings and death, of his resurrection from the dead, and ascension to heaven; they were a company of select men, chosen before of God, for this purpose; they were the most proper to be concerned herein, having been for a considerable time his intimates and associates:

because ye have been with me from the beginning; from the beginning of his ministry; for as soon as he entered on his public work, he called them to be followers of him; and who continued with him to the end, and therefore were the most capable of bearing a testimony concerning his person, doctrines, and works; of all he did and suffered, from first to last.