The God of peace will soon crush Satan under your feet. - Romans 16:20
Who is crushing whom in this verse? God is crushing Satan, thats clear for everyone. The thing that is not so trivial is this: How does he crush Satan? Didn’t he do it on the cross? That is the right religious answer, yes, the cross was the final blow, the ultimate demonstration of Gods manifold wisdom to the powers and principalities (Eph 3:10 + Phil 2).
But apparently there is still an actual need of crushing Satan right now, because he is kind of not dead and bothering with the christians in Rome that Paul is writing to. Now thousands of years later Satan is still active, still accusing brethren, deceiving kings of the earth and perverting our culture. There is still an actual need for some headcrushing!
The nontrivial thing about this scripture is that He is crushing Satan, but with our feet. God does not wave his magic wand and Satan is somehow crushed, he needs our feet and he wants us to be involved in this headcrushing. There is no place for escapism here, nor fatalism or some kind of superspiritual “God’s grace will somehow accomplish this without me beeing involved”. Your are still on the earth, you are not raptured yet, because God needs your feet to crush Satans head.