John 3:11
Truly, truly, I tell you, we [i.e., Jesus and His disciples] speak about what we know, and testify about what we have seen, but you do not accept our testimony.
John 3:32-33
He testifies concerning what He has seen and heard, but no one accepts His testimony.
Acts 20:21
[You know how] I testified to both Jews and Greeks [i.e., Gentiles], that they must repent [i.e., change their attitudes and behavior] toward God, and have faith toward our Lord Jesus Christ.
1 John 5:9
If we [are willing to] accept the testimony of people about matters, [surely we ought to accept that] the testimony of God is more reliable; because the testimony of God is that He has presented [confirming] testimony concerning [the identity and mission of] His Son.