The demons are weakened when the passions in us decrease through our keeping the commandments; and they are defeated totally when they are routed by dispassion, for then they no longer find anything through which they can enter the soul and fight against it. This is what is meant by "they will be weakened and defeated before thy face." (Maximos the Confessor)

Maximos is almost certainly quoting from the third verse of the ninth psalm.  Here is a contemporary translation:

I will give thanks to the Lord with my whole heart;
I will recount all of your wonderful deeds.
I will be glad and exult in you;
I will sing praise to your name, O Most High.

When my enemies turn back,
they stumble and perish before your presence.

For you have maintained my just cause;
you have sat on the throne, giving righteous judgment.
You have rebuked the nations; you have made the wicked perish;

It is God who maintains, God who gives judgment.  It is our role to give thanks, recount, be glad, and sing praise.