Sin is crouching at the door...

In one of the most famous Old Testament passages of all time, the LORD says to Cain, "...Sin is crouching at the door, and its desire is for you, but you must master it..." (Genesis 4:7, NASB). The picture is stark.  Sin is like a wolf, or a tiger, or a huge bear, waiting to pounce, waiting to destroy.  You have to go outside.  There will be a battle.  It will be to the death.  Who will win?
That's how sin is represented--as a powerful top predator (note also 1 Peter: "[the devil] roams about as a roaring lion, seeking whom he may devour."
We are just men and women, with no huge jaws and teeth, no giant paws and claws. How can we win?
The message is simple.  We have powers that no spiritual predator has:
First, assuming that we're watchful, there's always warning.  Cain had warning.  the LORD Himself warned Cain. In doing that, He set in stone for all time the fact that sin is always "crouching at the door," waiting... And so He warns us.  Sin waits.  But if you are watchful, you'll be in time to resist.
Second,  RESIST.  You cannot win if you do not fight.  you may wind up bloodied and hurt from the battle, but that's the nature of war.  You get hurt. However, it's like the man in the old myth, who grew stronger each time his adversary threw him to the ground. Every time you fight, you get stronger.  Every time you resist, you win.  Satan will say to you, "You cannot win, I am too powerful for you." And so it is. He is the mightiest of the fallen angels, and certainly mightier than you.  But he's wrong about not winning, because...
Third, you have the Lord.  "Greater is He who is in you than he who is in the world..." When you resist, you win.  When you fight back, you are the victor,  because even though you feel weak, you are mighty in Him. When you fail, there's another opportunity, because forgiveness is yours, and because your life is in Him. Satan is stronger than you, but he's not stronger than the Almighty, who is with you and in you.
Resist. Fight. Don't give up.
You may lose a battle, but as it is written, the righteous falls seven times, and arises again.  It's in getting back up, in resisting, in fighting UNTIL you win, that victory comes.
Never give up. Always resist. Always get up if you're defeated. Always.