'Testify' in the Bible

Once more I solemnly affirm to every man who receives circumcision [as a supposed requirement of salvation], that he is under obligation and required to keep the whole Law.

From now on let no one trouble me [by making it necessary for me to justify my authority as an apostle, and the absolute truth of the gospel], for I bear on my body the branding-marks of Jesus [the wounds, scars, and other outward evidence of persecutions—these testify to His ownership of me].