God's swearing by His creatures is a method adopted by the Quran at which the opponents of Islam have too often stumbled, but their objections are due to lack of reflection. The oaths of the Book have underlying in them secrets of a very deep nature. The critics, being unable to comprehend them, have taken them for a flaw. In order to understand this subject fully, we must consider the meaning of swearing.
In ordinary transactions or legal proceedings, when a person takes an oath, his object is simply to supply the deficiency of insufficient testimony. He really calls the Lord to witness when there is no other witness in the case; for the Almighty are the Knower of secrets and the best Witness in every case. The manner in which he intends God to bear testimony is by His action, viz., that the truth of his assertion shall be confirmed if the Almighty does not send down His punishment upon him after the oath, as a mark of His displeasure which must follow a false oath. It is for this reason, too, that a man is forbidden to swear by the name of any creature, for the latter has no power either to know his secrets or to punish him for a false oath.
The object and meaning of Divine oaths must, however, be distinguished from those of mortals. Divine laws reveal a twofold nature of the works of God: obvious and inferential. The former are easily comprehensible, and regarding them very few or no differences exist; but in the comprehension of the latter there is a liability of error and much difference of opinion. In the form of oath, the Supreme Being has called attention to what may be inferred from what is obvious.
To take the oaths, mentioned in the verses quoted above, we see that the sun and the moon, day and night, heaven and earth belong to the former class and their properties are known to all. But the same properties as found in the soul of man are not obvious. To lead to an inference of the existence of these properties in the spirit of man, the Creator has called to witness His obvious works. The brief oaths may thus be unfolded into a chain of reasoning. The hidden excellences possessed by the soul of man are inferred from the manifest working of the sun and the moon... Man is but a miniature universe, and in his soul is represented on a small scale all that exists in the external universe. By creating man, the Lord has as it were, enclosed in a nutshell the various forces existing in the world.
Now it is plain that the great bodies of the universe, for instance, have certain properties and forces which they employ in the service of God's creatures. It is, therefore, contrary to all reason to assert that man, who is above them all and greater than all of them, should be destitute of benefiting the rest of creation like them. Like the sun, he possesses a light the light of wisdom and knowledge - with which he can enlighten the world. Like the moon he borrows a light from the Most High, the original source of light, the light of vision, inspiration and revelation, which he transmits to those who are yet in the dark and have not attained to the perfection of humanity. It is sheer ignorance, then, to assert that prophethood is a pretence and that a message from on High, Divine Law and heavenly Books are mere impostures to achieve some private end.
Consider again how daylight renders manifest every path and reveals its ups and downs. The perfect man is the day of spiritual light. His appearance brings the different paths into view and points out the right from the wrong, for he is the bright day of truth and virtue. We observe, in like manner, that the night affords rest to the tired and the weary. The ever-spent laborer of the day welcomes the night and goes to rest, relieved of the day's toil.
Similarly, the perfect man comes to give rest to the world and to lighten the burden of men. With his inspirations and revelations from the source of wisdom and knowledge, he pours balm into the souls of all understanding men. Great truths, which wise people could not have discovered despite hard work, are disclosed with ease through the inspired one. Revelation, moreover, assists reason and covers up its faults, for it conceals its failings from the world. The wise man reforms himself and corrects his errors by the guidance and light of revelation and thus, with its aid, he saves himself from public exposure. This is the reason why a Greek philosopher, Plato, committed himself to the unwise act of making an offering to an idol, while no such act is recorded of any Muslim philosopher, because the latter had the perfect revelation of Prophet Muhammad for the guidance of reason. It will thus be understood why the Almighty has called attention to the covering of night in the form of an oath.
It is, moreover, clear that the perfect servants of the Lord take every distressed and fatigued person under their shelter like heaven. The prophets especially benefit the world with the showers of their blessings and favors as heaven does with the showers of rain. They, likewise, possess the properties of the earth, and from their purified souls various sorts of trees of knowledge and truth grow up in abundance and, with their flowers and fruits, they bless the world. Thus the laws which we read in the open book of nature are a witness to the hidden laws and their testimony has been described in the form of oaths in the verses quoted above. How excellent is the wisdom displayed in the Divine Word! And this is the Word which has been proclaimed through the mouth of an unlettered son of the desert. Had it not been the wise Word of God, the educated sons of the wordly-wise would not thus have been driven to their wit's end and, failing at last to realize the true sense with their imperfect reason, have objected to these passages where treasures of wisdom lay concealed.
Thus we see that when worldly wisdom fails to discover the true meaning of words, which are afterwards shown to be pregnant with meaning, this constitutes a strong testimony to the superhuman origin of the words. Such has been the case with regard to the oaths of the Quran which were considered as weak and vulnerable points, but, now when the mystery has been solved and light has been thrown upon their true significance, all sensible persons should derive pleasure from reflecting on this subject.