And ye also shall bear witness, because ye have been with me from the beginning.
The Spirit would testify directly through the disciples. They had been with the Lord from the beginning of His public ministry and were especially qualified to tell of His Person and work. If anyone could have found any imperfection in the Lord, those who had been with Him the most would have. But they never knew Him to commit a sin of any kind. They could testify to the fact that He was the sinless Son of God and the Saviour of the world.