And God, which knoweth the hearts - Acts 1:24. God thus knew whether they were true converts or not, and gave a demonstration that he acknowledged them as his.
Giving them the Holy Ghost - Acts 10:45-46.

And God which knoweth the hearts - Ο καρδιογνωϚης Θεος. We had this epithet of the Divine Being once before; see Acts 1:24, and the note there: it occurs no where else in the New Testament.
Bare them witness - Considered them as proper or fit to receive the Gospel of Christ. It is properly remarked by learned men, that μαρτυρειν τινι, to bear witness to any person, signifies to approve, to testify in behalf of. Here it signifies that, as God evidently sent the Gospel to the Gentiles, and, by the preaching of it, conveyed the Holy Spirit to them who believed, and as he can make no improper judgment of any who knows all hearts and their secrets, therefore what he had done was right: he saw that it was time for them to receive the Gospel; and he saw that they might be safely trusted with this heavenly deposit; and the experience of eighteen hundred years has justified the conduct of God.

And God which knoweth the hearts,.... Of all men; he being omniscient, the searcher of the hearts, and the trier of the reins of the children of men, knew with what sincerity Cornelius sent for Peter; and with what vehement desire and longing expectation he and his family and friends waited for his coming; and with what earnestness, diligence, and affection they attended to what he said:
bore them witness, giving them the Holy Ghost, even as he did unto us; God bore a testimony, and showed his well pleasedness in the whole of this affair, by bestowing upon them not only the regenerating and sanctifying grace of the Spirit; but his extraordinary gifts, such as speaking with divers tongues, even in like manner as these were bestowed on the apostles themselves, on the day of Pentecost, though they were uncircumcised persons; for the drift of Peter's oration is to show, that circumcision was not necessary to salvation.

God, which knoweth the hearts--implying that the real question for admission to full standing in the visible Church is the state of the heart. Hence, though that cannot be known by men, no principle of admission to church privileges which reverses this can be sound.

God bare them witness - That he had accepted them, by giving them the Holy Ghost.