"Lest our"

1. 2 Cor. 9: 3
     3 Yet have I sent the brethren, lest our boasting of you should be in vain in this behalf; that, as I said, ye may be ready:
2. Alma 12: 21
     21 What does the scripture mean, which saith that God placed cherubim and a flaming sword on the east of the garden of Eden, lest our first parents should enter and partake of the fruit of the tree of life, and live forever? And thus we see that there was no possible chance that they should live forever.