1-john 4:14

And we have seen - Jesus Christ manifested in the flesh; see 1 John 1:1, etc.; and do testify - bear witness, in consequence of having the fullest conviction, that the Father sent the son to be the Savior of the world. We have had the fullest proof of this from his doctrine and miracles, which we heard and saw during the whole time that he sojourned among men.

And we have seen - Notes on 1 John 1:1.

And do testify - Notes, 1 John 1:3. That is, we who are apostles bear witness to you of this great truth, that God has sent his Son to be a Saviour. Compare the notes at John 20:31. The reason why this is referred to here is not quite apparent, but the train of thought in this passage would seem to be this: The writer is discoursing of the love of God, and of its manifestation in the gift of the Saviour, and of the proper influence which it should have on us. Struck with the greatness and importance of the subject, his mind adverts to the "evidence" on which what he was saying rested - the evidence that the Father had really thus manifested his love. That evidence he repeats, that he had actually seen him who had been sent, and had the clearest demonstration that what he deemed so important had really occurred.

4:14 And in consequence of this we have seen and testify that the Father sent the Son - These are the foundation and the criteria of our abiding in God and God in us, the communion of the Spirit, and the confession of the Son.