The variety of natural phenomena and the laws they exhibit give evidence of the personality of God and the existence of his will. A being without will, acting by necessity of nature, acts with unswerving uniformity. Heaven and earth, plant and animal, all creatures great and small, bear witness, in their structure and relations, in their functions and mutual service and helpfulness, to the wisdom and goodness of God. Above all is this visible in man, the highest of earthly beings, the microcosm, the rational creature, the discoverer and inventor of arts and sciences. In the laws and statutes which were given to him for the service of God, and in the customs of other nations which take the place of our divine law, we see God's kindness to man in securing his comfort in this world and reward in the next. Pride is the great enemy of man, because it prevents him from appreciating what he owes to God's goodness. Pride makes him feel that he deserves more than he gets, and blinds him to the truth.[122] We all recognize the duty of gratitude to a fellow man who has done us a favor, although all such cases of benefit and service between man and man, not excepting even the kindness of a father to his child, will be found on examination to be of a selfish nature. The benefit to self may not in all cases be conscious, but it is always there. It is a father's nature to love his child as part of himself. Moreover, these human favors are not constant, and the person benefited stands comparatively on the same level of existence and worth as his benefactor. How much greater then is the duty incumbent upon us to appreciate God's favors which are not selfish, which are constant, and which are bestowed by the greatest of all beings upon the smallest of all in respect of physical strength. The only way in which man can repay God for his kindness, and show an appreciation thereof is by submitting to him and doing those things which will bring him nearer to God. In order to realize this it is necessary to abandon the bad qualities, which are in principle two, love of pleasure and love of power. The means enabling one to obtain this freedom are to abstain from too much eating, drinking, idling, and so on, for the first, and from too much gossip, social intercourse, and love of glory for the second. It may be difficult to do this, but one must make up one's mind to it, like the invalid who is ready to lose a limb in order to save his life. The problem of free will is perplexing indeed and interferes with the proper attitude toward God and his worship. The best way out of the difficulty is to act as if we were free, and on the other hand to have confidence in God as the author of everything.