'Two by Two' in the Bible

two by two they have come in unto Noah, unto the ark, a male and a female, as God hath commanded Noah.

And they come in unto Noah, unto the ark, two by two of all the flesh in which is a living spirit;

to the east the Levites are six; to the north daily four, to the south daily four, and to the gatherings two by two,

and he doth call near the twelve, and he began to send them forth two by two, and he was giving them power over the unclean spirits,

Now after this the Lord appointed seventy others, and sent them out ahead of Him, two by two, into every city and place where He was about to go.