'Built an Altar' in the Bible

And Moses built an altar, and called the name of it JEHOVAH-nissi:

And Moses wrote all the words of the LORD, and rose early in the morning, and built an altar under the hill, and twelve pillars according to the twelve tribes of Israel.

And when Aaron saw it, he built an altar before it; and Aaron made proclamation, and said, To-morrow is a feast to the LORD.