I find it interesting that in the New Testament when Jesus encounters Nicodemus and mentions being "born again," he seems befuddled by the question or the comment that Jesus makes. But Jesus, in his rebuke to him, mild as it was, suggested that he should know that. And yet, the idea of being born again is not mentioned in the Old Testament, but what is mentioned is being circumcised of heart, a heart change that's necessary in order to fulfill what God wants in his commandments. And, of course, the commands can come to us, but they don't give us a desire to keep them. And so, the command to circumcise their heart was to recognize that the real problem was their heart condition, their love for things other than God and his glory. And so, it was really a call to conversion, and as long as that did not happen, it was never going to be that Israel would be the nation, the people would be the people that God had called them to be. And so we learn in Moses, in his last address to the people, tells them that despite all the miracles they had seen, all the things God had done for them, they still did not believe because the Lord had not given them a heart to believe. But then it goes on to say that their children, the ones that they thought God would bring into the Promised Land and have them slaughtered, he would actually circumcise their heart so that they would believe. And you read God, in the Prophets, will look back at that first generation that was in the desert as a faithful generation, and evidently it was because God had circumcised their hearts. And so, that's what's needed in the old covenant, and in the new covenant it's talked about in terms of being "born again.