New Revised Standard Version
For John had been telling Herod, “It is not lawful for you to have your brother’s wife.”

New American Bible
John had said to Herod, “It is not lawful for you to have your brother’s wife.”

Douay-Rheims Bible
For John said to Herod: It is not lawful for thee to have thy brother's wife.

For John said to Herod: It is not lawful for thee to have thy brother's wife.

It is.

Leviticus 18:16 Thou shalt not uncover the nakedness of thy brother's wife: because it is the nakedness of thy brother.

Leviticus 20:21 He that marrieth his brother's wife, doth an unlawful thing: he hath uncovered his brother's nakedness. They shall be without children.

1 Kings 22:14 But Micheas said to him: As the Lord liveth, whatsoever the Lord shall say to me, that will I speak.

Ezekiel 3:18,19 If, when I say to the wicked, Thou shalt surely die: thou declare it not to him, nor speak to him, that he may be converted from his wicked way, and live: the same wicked man shall die in his iniquity, but I will require his blood at thy hand. . . .

Matthew 14:3,4 For Herod had apprehended John and bound him, and put him into prison, because of Herodias, his brother's wife. . . .

Acts 20:26,27 Wherefore I take you to witness this day that I am clear from the blood of all men. . . .

Acts 24:24-26 And after some days, Felix, coming with Drusilla his wife, who was a Jew, sent for Paul and heard of him the faith that is in Christ Jesus. . . .