'Twos' in the Bible

In twos, male and female, they went into the ark with Noah, as God had said.

And when he sees war-carriages, horsemen by twos, war-carriages with asses, war-carriages with camels, let him give special attention.

See, here come war-carriages with men, horsemen by twos: and in answer he said, Babylon is made low, is made low, and all her images are broken on the earth.

The arrowsnake will make her hole and put her eggs there, and get her young together under her shade: there the hawks will come together by twos.