It is.

Leviticus 18:16
You must not have sexual relations with your brother's wife; that would shame your brother.

Leviticus 20:21
If a man marries his brother's wife, it is an act of impurity. He has uncovered the nakedness of his brother; they shall be childless.

1 Kings 22:14
But Micaiah said, "As surely as the LORD lives, I will speak whatever the LORD tells me."

Ezekiel 3:18, 19
If I say to the wicked man, 'You will surely die, ' but you do not warn him or speak out to warn him from his wicked way to save his life, that wicked man will die in his iniquity, and I will hold you responsible for his blood. . . .

Matthew 14:3, 4
Now Herod had arrested John and bound him and put him in prison on account of Herodias, his brother Philip's wife, . . .

Acts 20:26, 27
Therefore I testify to you this day that I am innocent of the blood of all men. . . .

Acts 24:24-26
After several days, Felix returned with his wife Drusilla, who was a Jewess. He sent for Paul and listened to him speak about faith in Christ Jesus. . . .