Acts 22:15

Ὅτι ἔσῃ μάρτυς αὐτῷ πρὸς πάντας ἀνθρώπους ὧν ἑώρακας καὶ ἤκουσας.

Oti esē martys aytō pros pantas anthrōpoys ōn eōrakas kai ēkoysas.

King James Version (KJV)

For thou shalt be his witness unto all men of what thou hast seen and heard.

Modern English

You will be his witness to all people of what you have seen and heard.