1 John 5:10-11

5:10 (The one who believes in the Son of God has the testimony in himself; the one who does not believe God has made him a liar, because he has not believed in the testimony that God has testified concerning his Son.) 5:11 And this is the testimony: God has given us eternal life, and this life is in his Son.

John 8:13-14

8:13 So the Pharisees objected, “You testify about yourself; your testimony is not true!” 8:14 Jesus answered, “Even if I testify about myself, my testimony is true, because I know where I came from and where I am going. But you people do not know where I came from or where I am going.