An efficient cause is defined as the agent of an object as that which causes change and motion to start or stop. The human heart is a vivid example of an efficient cause. It cause the flow of blood thorough the human body and when it stops we die. But this is not the end of efficient causality. What causes the heart to beat, pump or contract and release? The obvious answer is the human form or soul with its built in intelligence to form the heart and function as it does. But the final efficient cause is God who makes the soul and all other creatures to be and move.
Thomas Aquinas explains the relationship between between the first cause who is God and the activity of the human soul which is the secondary cause. The activity by which he second cause acts is an effect of the first cause, 'for the first case aids the second cause,' making it act. Therefore, the first cause is more a cause than the second cause of that activity in virtue of which an effect is produces by the second cause." (Thomistic Institute 2000 by Michael J. Doods, O.P.)
The universe we live in consists of a series of interdependent causalities all dependent on the First Cause. "The First Cause is neither intelligence not Soul nor Nature; on the contrary,it is above Intelligence and Soul and nature, because it creates all things." For this reason, it is also present to all things. Other causes act under its influence, not to give being but only to give form. The Soul, for esample, may cause a thing to live (to have form and life, but it does not cause the thing to be." (Ibid., Michael J. Dodds,O.P.)
The human soul causes the formation of the heart and its beating but the author of the heart, soul and man is God who is present to the heart and soul of man in such a way as to empower it to be and act as it does. God is the great Efficient Cause which causes change and motion and without whom there would not be change or motion.