And out of the ground made the LORD God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil. Every tree that is pleasant to the sight, etc. - If we take up these expressions literally, they may bear the following interpretation: the tree pleasant to the sight may mean every beautiful tree or plant which for shape, color, or fragrance, delights the senses, such as flowering shrubs, etc.
And good for food - All fruit-bearing trees, whether of the pulpy fruits, as apples, etc., or of the kernel or nut kind, such as dates, and nuts of different sorts, together with all esculent vegetables.
The tree of life - חיים chaiyim; of lives, or life-giving tree, every medicinal tree, herb, and plant, whose healing virtues are of great consequence to man in his present state, when through sin diseases of various kinds have seized on the human frame, and have commenced that process of dissolution which is to reduce the body to its primitive dust.
Yet by the use of these trees of life - those different vegetable medicines, the health of the body may be preserved for a time, and death kept at a distance. Though the exposition given here may be a general meaning for these general terms, yet it is likely that this tree of life which was placed in the midst of the garden was intended as an emblem of that life which man should ever live, provided he continued in obedience to his Maker. And probably the use of this tree was intended as the means of preserving the body of man in a state of continual vital energy, and an antidote against death. This seems strongly indicated from Genesis 3:22.
And the tree of knowledge of good and evil - Considering this also in a merely literal point of view, it may mean any tree or plant which possessed the property of increasing the knowledge of what was in nature, as the esculent vegetables had of increasing bodily vigor; and that there are some ailments which from their physical influence have a tendency to strengthen the understanding and invigorate the rational faculty more than others, has been supposed by the wisest and best of men; yet here much more seems intended, but what is very difficult to be ascertained. Some very eminent men have contended that the passage should be understood allegorically! and that the tree of the knowledge of good and evil means simply that prudence, which is a mixture of knowledge, care, caution, and judgment, which was prescribed to regulate the whole of man's conduct. And it is certain that to know good and evil, in different parts of Scripture, means such knowledge and discretion as leads a man to understand what is fit and unfit, what is not proper to be done and what should be performed. But how could the acquisition of such a faculty be a sin? Or can we suppose that such a faculty could be wanting when man was in a state of perfection? To this it may be answered: The prohibition was intended to exercise this faculty in man that it should constantly teach him this moral lesson, that there were some things fit and others unfit to be done, and that in reference to this point the tree itself should be both a constant teacher and monitor. The eating of its fruit would not have increased this moral faculty, but the prohibition was intended to exercise the faculty he already possessed. There is certainly nothing unreasonable in this explanation, and viewed in this light the passage loses much of its obscurity. Vitringa, in his dissertation Deuteronomy arbore prudentiae in Paradiso, ejusque mysterio, strongly contends for this interpretation. See more on Genesis 3:6 (note).