I am One who bears witness of Myself, and the Father who sent Me bears witness of Me."
John 8:18
Surrounding context
8:17 It is also written in your law that the testimony of two men is true.
8:18 I am One who bears witness of Myself, and the Father who sent Me bears witness of Me."
8:19 Then they said to Him, "Where is Your Father?" Jesus answered, "You know neither Me nor My Father. If you had known Me, you would have known My Father also."