“Even as the testimony of Christ was confirmed in you:”
King James Version (KJV)
1:6 The testimony of Christ - The gospel. Was confirmed among you - By these gifts attending it. They knew they had received these by the hand of Paul: and this consideration was highly proper, to revive in them their former reverence and affection for their spiritual father.
1Co 1:6 Even as the testimony of Christ was confirmed in you. It was confirmed by the fruits which it brought forth; their belief and the spiritual gifts which were bestowed upon some of them.