As we know, Adam and Eve succumbed to Satan’s temptations to eat the fruit and disobeyed God who had commanded them not to eat from the tree of knowledge of good and evil. As a consequence, they were separated from God’s presence physically and spiritually — an event we refer to as the Fall. They became mortal — just as we are — subject to sin, disease, all types of suffering, and ultimately death. But it wasn’t all bad because they could now feel great joy. “Adam fell that men might be; and men are, that they might have joy.” ( 2 Nephi 2:25 ) But as they were obedient to the Gospel of Jesus Christ Adam and Eve were able to receive God’s inspiration, revelation, and even visits from heavenly messengers.
Once out of the garden, they were able to progress and learn to become more like our Heavenly Father. In addition, they could have children, which meant the rest of God’s spirit children (all of us) could come to Earth, experience physical bodies, and be proven by our daily choices. Just like Adam and Eve, there are consequences to all our choices, good or bad. Lasting happiness and progression come from choosing to do what God wants us to do. The key word is “choosing.” Generally God does not step in and prevent us from making the poor choices Satan tempts us to make. He will, however, offer his love, divine guidance, and warnings when we open our heart to Him.
Talk Source: http://mormon.org/plan-of-happiness