This cannot mean a merely natural heart, it must mean a renewed heart, because there are no perfect hearts by nature. There is no one in this sense that doeth good and sinneth not, for every child of Adam has gone astray like a lost sheep, has done the things he ought not, and left undone the things he ought to have done, and the whole world has become guilty before God. There are no naturally perfect hearts. It must mean, then, a heart renewed by the Holy Ghost, put right with God, and then kept right. A heart cannot be kept right until it has been _put right_, and that is the secret of the failure with some of you. You are trying to bring forth fruits before the tree is planted. You are looking for the fruits of a perfect heart before you have got one. You may well be disappointed. You must get your heart renewed, and then kept right by the power of the Holy Ghost. Then, what does this perfect heart imply? 1. _A heart perfect in its loyalty to God_, thoroughly given over to God's side, irrespective of consequences,--_loyal_. These are the hearts that God wants. This was the difference between David and Saul. There was not so much difference in the greater part of Saul's outward life, when compared with the life of David. It was only the prophet Samuel, perhaps, who knew the difference, and a few close observers; but the difference was, that David was loyal to God, and God calls him, for this reason, a man after His own heart. From the first calling of David from the sheepfolds, right to the end, with one or two exceptions, during the whole of his life, he was loyal to God, and, if you will carefully search his history, you will find that in all his wars, and all his dealings with the nations round about, and with the leaders of affairs in his own kingdom--in everything, David was loyal to God. It was the interests of God's kingdom that lay at David's heart--not his own honor, ease, or aggrandizement--not his own fame or riches, or building himself a house--it was the house of his God that was dear to his heart. He was loyal; whereas Saul was loyal only as far as it served his own purposes and interests. Oh! how many such Sauls there are in these days. When God's commandments went counter with his notions, he openly set God at naught, and did as he liked. He sacrificed God's interests to his own. He was unloyal at heart, hence he was a traitor, and never could learn the way of the Lord. He was never perfect towards the Lord his God, and, at last, God cast him off, and Samuel did also, and you know what his end was. Just the difference between the two--loyal and unloyal. A heart perfect towards God! What does it mean? It means--