But of the tree of the knowledge of good and evil you shall not eat, for in the day that you eat of it you shall surely die. Genesis 2:17. FH 140.1
The Lord knew that Adam and Eve could not be happy without labor; therefore He gave them the pleasant employment of dressing the garden. And, as they tended the things of beauty and usefulness around them, they could behold the goodness and glory of God in His created works. Adam and Eve had themes for contemplation in the works of God in Eden, which was heaven in miniature. God did not form them merely to contemplate His glorious works; therefore He gave them hands for labor, as well as minds and hearts for contemplation. If the happiness of His creatures consisted in doing nothing, the Creator would not have given them their appointed work. In labor, Adam and Eve were to find happiness as well as meditation. They could reflect that they were created in the image of God, to be like Him in righteousness and holiness. Their minds were capable of continual cultivation, expansion, refinement, and noble elevation; for God was their teacher, and angels were their companions. FH 140.2
The Lord placed Adam and Eve upon probation, that they might form characters of steadfast integrity for their own happiness and for the glory of their Creator. He had endowed the holy pair with powers of mind superior to any other living creature that He had made. Their mental powers were but little lower than those of the angels. They could become familiar with the sublimity and glory of nature, and understand the character of their heavenly Father in His created works. Everything that their eyes rested upon in the immensity of the Father's works, provided with a lavish hand, testified of His love and infinite power.... FH 140.3
The first great moral lesson given to Adam and Eve was that of self-denial. The reins of self-government were placed in their hands. Judgment, reason, and conscience were to bear sway.... Adam and Eve were permitted to partake of every tree in the garden save one. There was only a single prohibition. The forbidden tree was as attractive and lovely as any of the trees in the garden. It was called the tree of knowledge, because in partaking of that tree, of which God had said, “Thou shalt not eat of it,” they would have a knowledge of sin, an experience in disobedience.—The Review and Herald, February 24, 1874. FH 140.4