And you also bear testimony. Christ means that the testimony of the Spirit will not be of such a nature that the apostles shall have it for their private advantage, or that they alone shall enjoy it, but that by them it will be widely diffused, because they will be organs of the Holy Spirit, as indeed, he spoke by their mouth. We now see in what way faith is by hearing, (Romans 10:17,) and yet it derives its certainty from the seal and earnest of the Spirit, (Ephesians 1:13, 14.) Those who do not sufficiently know the darkness of the human mind imagine that faith is formed naturally by hearing and preaching alone; [1] and there are many fanatics who disdain the outward preaching, and talk in lofty terms about secret revelations and inspirations, (enthousiasmous) But we see how Christ joins these two things together; and, therefore, though there is no faith till the Spirit of God seal our minds and hearts, still we must not go to seek visions or oracles in the clouds; but the word, which is near us, in our mouth and heart, (Romans 10:8,) must keep all our senses bound and fixed on itself, as Isaiah says beautifully: My Spirit that is upon thee, and my words which I have put in thy mouth, shall not depart out of thy mouth, nor out of the mouth of thy seed, nor out of the mouth of thy seed's seed saith the Lord, from henceforth and for ever, (Isaiah 59:21.) Because you are with me from the beginning. This clause was added in order to inform us that so much the greater credit is due to the apostles on this ground, that they were eye-witnesses of what they relate; as John says, what we have heard, what we have seen, what our hands have handled, we declare to you; (1 John 1:1) for thus the Lord intended to provide for our welfare in every possible way, that nothing might be wanting for a full confirmation of the Gospel.

Footnotes

1 - "De la seule ouye et predication."

Ye also shall bear witness - You shall be witnesses to the world to urge on them the evidences that the Lord Jesus is the Messiah.
Have been with me - They had for more than three years seen his works, and were therefore qualified to bear witness of his character and doctrines.
From the beginning - From his entrance on the public work of the ministry, Matthew 4:17-22. Compare Acts 1:21-22.

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.

ye also shall bear witness--rather, "are witnesses"; with reference indeed to their future witness-bearing, but putting the emphasis upon their present ample opportunities for acquiring their qualifications for that great office, inasmuch as they had been "with Him from the beginning." (See on Luke 1:2).

Ye also shall bear witness. The apostles had been "with him from the beginning," and knew all the facts. If he was true, they knew it; if he stilled the waves and raised the dead, they knew it; if he rose from the tomb, they knew it. They bore witness to him by word and left their words to us. They bore witness by life, gave up all for him and died for their testimony. Such testimony is the strongest human testimony ever offered to any fact.