If I bear witness of myself, my witness is not true.
John 8:13
The Pharisees, therefore, said to him, 'Thou of thyself dost testify, thy testimony is not true;'
John 8:14
Jesus answered and said to them, 'And if I testify of myself -- my testimony is true, because I have known whence I came, and whither I go, and ye -- ye have not known whence I come, or whither I go.
John 8:54
Jesus answered, 'If I glorify myself, my glory is nothing; it is my Father who is glorifying me, of whom ye say that He is your God;
Proverbs 27:2
Let another praise thee, and not thine own mouth, A stranger, and not thine own lips.
Revelation 3:14
'And to the messenger of the assembly of the Laodiceans write: These things saith the Amen, the witness -- the faithful and true -- the chief of the creation of God;