2 The infinitive absolute with the finite verb stresses the point. The primary meaning of the verb is “to witness; to testify.” It alludes to Joseph’s oath, which was tantamount to a threat or warning.
3 The idiom “see my face” means “have an audience with me.”

In other versions

But Judah said to him, “The man solemnly warned us, saying, ‘You shall not see my face unless your brother is with you.’

But Judah said to him, “The man warned us solemnly, ‘You will not see my face again unless your brother is with you.’

But Judah said to him, “The man specifically warned us, ‘You will not see me again unless your brother is with you.’

But Judah said, “The man was serious when he warned us, ‘You won’t see my face again unless your brother is with you.’

Then Judah said to him, “The man solemnly admonished us, saying, ‘You shall not see my face unless your brother is with you.’

And Judah spake unto him, saying, The man did solemnly protest unto us, saying, Ye shall not see my face, except your brother be with you.

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