What would make life better?  Like Israel, we live in the wilderness and grow discontent.  We are secure in Christ, but not yet in the New Heavens and Earth.  The frustrations of life often make us focus on what we do not have.  Numbers 21:4-9, shows that discontentment is sin and frustration with God's providence.  But it also shows how the glory of the gospel and Christ's saving work is the cure of discontentment.