In life there is a tendency where those who fear God begin to worry if their God will save them because they reckon themselves to have gone through a lot and their patience levels begin to dry up. In that time, they seek to be like the world; because the worldly man is flourishing in the interim.
The verse reminds us of God's promise, that he will put a clear distinction between them that serve him and them that serve him not. It's one thing for God to put a distinction between the righteous and the wicked; it's another thing for him to put a mark between those that serve him and those that do not serve him.
This is why if a man has chosen to be righteous, let him be righteous, and him that has chosen to be wicked let him be wicked. For of certainty, God will put a mark between the two.
Prophetic Declarations
Halleluyah. Amen