Final answer:
God kept Adam and Eve from returning to the Garden of Eden and accessing the Tree of Life by placing cherubim and a fiery, ever-turning sword to guard the Tree after they ate from the Tree of Knowledge of Good and Evil.
Step-by-step explanation:
The question How did God keep Adam and Eve out from the Garden of Eden and from eating from the Tree of Life? refers to the biblical account found in the Book of Genesis. When Adam and Eve disobeyed God by eating from the Tree of Knowledge of Good and Evil, God decided to banish them from the Garden of Eden to prevent them from eating from the Tree of Life and becoming immortal. Genesis 3:24 states that God placed cherubim and a flaming sword flashing back and forth to guard the way to the Tree of Life. This act of guarding the Tree effectively prevented Adam and Eve from returning to the Garden and accessing eternal life.