The lion is a predator.  The Psalm writer would have known this very well.  They sneak around and stalk their prey and once they pounce on you, it's too late.  In Job, Satan is compared to a lion, pacing back and forth on the earth seeking someone to devour!  But God's people are often sheep in the psalms; a favorite dinner of the lion.  Sheep are far from predators, they are meek and innocent and defensless.

Evil people, bad people, often prey upon the innocent.  We see that over and over in our world.  But the good news is that, contrary to what we might expect, it is the lions that will go hungry and it is those who seek the LORD that shall lack no good thing!

Even when it seems that evil is prevailing, in the end, it is those who truly follow God who shall emerge victorious!