'Twelve' in the Bible

All the days of Seth were nine hundred twelve years, then he died.

Twelve years they served Chedorlaomer, and in the thirteenth year, they rebelled.

As for Ishmael, I have heard you. Behold, I have blessed him, and will make him fruitful, and will multiply him exceedingly. He will become the father of twelve princes, and I will make him a great nation.

These are the sons of Ishmael, and these are their names, by their villages, and by their encampments: twelve princes, according to their nations.

It happened, while Israel lived in that land, that Reuben went and lay with Bilhah, his father's concubine, and Israel heard of it. Now the sons of Jacob were twelve.

They said, "We, your servants, are twelve brothers, the sons of one man in the land of Canaan; and behold, the youngest is this day with our father, and one is no more."

We are twelve brothers, sons of our father; one is no more, and the youngest is this day with our father in the land of Canaan.'

All these are the twelve tribes of Israel, and this is what their father spoke to them and blessed them. He blessed everyone according to his blessing.