“A person’s entire heart and all his confidence must be placed in God alone and in no one else. For to “have” God, you can easily see, is not to take hold of Him with our hands or to put Him in a bag <like money> or to lock Him in a chest <like silver vessels>. Instead, to “have” Him means that the heart takes hold of Him and clings to Him. To cling to Him with the heart is nothing else than to trust in Him entirely. For this reason God wishes to turn us away from everything else that exists outside him and to draw us to Himself [John 6:44]. For He is the only eternal good [Matthew 19:17].”
Martin Luther, Large Catechism, Explanation of the First Commandment “You shall have no other gods”.