'First born' in the Bible

And Joshua charged them with an oath at that time, saying, Cursed be the man before LORD who rises up and builds this city Jericho. With the loss of his first-born he shall lay the foundation of it, and with the loss of his younges

And [this] was the lot for the tribe of Manasseh, for he was the first-born of Joseph. As for Machir the first-born of Manasseh, the father of Gilead, because he was a man of war, therefore he had Gilead and Bashan.