Jn 6:63, Jn 17:8
At first, people heard the testimony of the Samaritan woman and believed in Jesus, but later they came to believe that Jesus was the Christ, not because of that testimony but because of the words of Christ. (Jn 4:39-42)
Jn 4:39 And many of the Samaritans of that city believed on him for the saying of the woman, which testified, He told me all that ever I did. 40 So when the Samaritans were come unto him, they besought him that he would tarry with them: and he abode there two days. 41 And many more believed because of his own word; 42 And said unto the woman, Now we believe, not because of thy saying: for we have heard him ourselves, and know that this is indeed the Christ, the Saviour of the world.
We also share the gospel through our testimonies. But the more accurate gospel is to testify that Jesus is the Christ through the words of Christ. (Jn 6:63, Jn 17:8)
Jn 6:63 It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life.
Jn 17:8 For I have given unto them the words which thou gavest me; and they have received them, and have known surely that I came out from thee, and they have believed that thou didst send me.