Why did Heavenly Father give Adam 2 commandments knowing he would have to sin to keep the one? Do not Partake of the Fruit and Multiply and replenish the Earth.
First of all, we need to keep in mind that Adam and Eve did not sin while in the Garden of Eden, they transgressed the law which brought with it consequences. In order for us to commit a sin we need to be able to know good from evil, which was not the case with Adam and Eve in the garden. In Moses 5: 11 “And Eve, his wife, heard all these things and was glad, saying: Were it not for our transgression we never should have had aseed, and never should have bknown good and evil…” Also keep in mind the second Article of Faith which states: “We believe that men will be punished for their own sins, and not for Adam’s transgression.” Adam and Eve were actually given four commandments in the Garden of Eden. They were told to multiply and replenish the earth, they were to govern the earth wisely, they were not to partake of the fruit of the tree of knowledge of good and evil, and they were to cleave unto each other. Adam and Eve had to choose as they could not obey both commandments, to multiply and replenish the earth and not partake of the fruit of the tree of knowledge. The Lord would not take away their free agency by making the choice for them.
President Joseph Fielding Smith wrote: “The Lord said to Adam that if he wished to remain as he was in the garden, then he was not to eat the fruit, but if he desired to eat it and partake of death he was at liberty to do so. In essence the Lord told Adam that there were two directions to go, each with its unique consequences—and that Adam was to choose which one.”
Lehi tells us in 2 Nephi 2: 22-23 that Adam and Eve knew no sin. We are fortunate that they transgressed the commandment not to partake of the forbidden fruit. Otherwise we would not be and they would have remained in the Garden in a state of innocence. In 26 Lehi further states: “…And because they are redeemed from the fall they have become free forever, knowing good from evil: to act for themselves and not to be acted upon..”
The Lord knew the choice Adam and Eve would make, but He allowed them to utilize their free agency, and He provided a Savior for all of us. This is the great plan of salvation that was presented and which we accepted in the pre-existence.