'Testify' in the Bible

and one in a certain place did testify fully, saying, 'What is man, that Thou art mindful of him, or a son of man, that Thou dost look after him?

for He doth testify -- 'Thou art a priest -- to the age, according to the order of Melchisedek;'

and testify to us also doth the Holy Spirit, for after that He hath said before,