All things naturally tend to God implicitly, but not explicitly. That this may appear clearly it should be observed that a secondary cause can influence its effect only in so far as it receives the power of the first cause. The influence of an efficient cause is to act; that of a final cause is to be sought or desired. A secondary agent acts only by the efficacy of the first agent existing in it; similarly a secondary end is sought only by reason of the worth of the principal end existing in it inasmuch as it is subordinated to the principal end or has its likeness.
Accordingly, because God is the last end, He is sought in every end, just as, because He is the first efficient cause, He acts in every agent.
Thomas Aquinas, Disputed Questions on Truth 22.2