Leviticus 20:16
And if a woman approach unto any beast, and lie down thereto, thou shalt kill the woman, and the beast: they shall surely be put to death; their blood shall be upon them. And if a woman approach unto any beast, and lie down thereto, thou shalt kill the woman, and the beast: they shall surely be put to death; their blood shall be upon them.
The verse strictly forbids a woman to approach any beast for sexual union with it. It belongs with the sexual prohibitions of Leviticus 18 and 20, placed in the February 17 reading of Leviticus 18-20 within the week covering Leviticus 5-23 on sacrificial laws, consecration and duties of priests, yearly feasts, clean and unclean animals, leprosy and houses, and moral laws. It states a prohibition based on moral considerations and therefore remains in force. It belongs to the civil laws given under Israel's theocracy, among prohibitions whose violation could make offspring ineligible for entry into the assembly of Jehovah.
It was given to Israel in contrast to the customs of the surrounding nations and reflects practices actually done by the Canaanite and heathen nations, with danger that the custom would be brought among the Hebrews. It exposes the extent of that evil and its destructive moral consequences, as a grave moral degradation that drives humanity downward. The nations the Lord cast out of the Holy Land before Israel had given themselves to pagan abominations with Satan ruling through the flesh, yet God in mercy gave them four hundred years of hope and sent His servants to sojourn among them to win them to the right way. When they filled up their cup of iniquity, blotting them from the earth became a blessing to future generations.
The chapter records the practices and judgments connected with those nations without explaining the specific act or penalty of verse 16. Such human-beast unions were real and able to reproduce in the stronger physical condition of people and animals just after the Flood, whereas the degenerated and weakened animal nature of today can no longer propagate such crosses. The monkeys in all their varieties are a degraded distortion of man as God's masterpiece, caused by sin rather than evolution, and were not part of God's original beautiful creation, though God did not create sin itself.