Psalm 37:37-38

³⁷ Mark the blameless man, and observe the upright;
For the future of that man is peace.
³⁸ But the transgressors shall be destroyed together;
The future of the wicked shall be cut off

Mark - regard, watch

Blameless - innocent, person of integrity, 

Observe - see, view

Peace - safe, well-being

Transgressors - rebels, offenders

Mark the blameless man - In contrast with what happens to the transgressors. The argument is, "Look upon that man in the end, in contrast with the wicked man.  The end of the two shows that there is an advantage in knowing God, He is the friend of the righteous. 

And behold the upright - For the end of that man is peace.  In the one case, it is ultimate disaster and ruin; in the other, it is ultimate peace and prosperity. The future of the wicked shall be "followed by" death and ruin; The future of the righteous man - the whole future - would be peace;

(a) as a general rule, peace or calmness in death is the result of a relationship with God and

(b) in the coming world, where there will be perfect and eternal peace.

As a usual fact religious men die calmly and peacefully, sustained by hope and by the presence of God; they are blessed forever beyond the grave.

Where do you stand? Do you have a saving relationship with God the Father through His Son Jesus who died to obtain your salvation? Or have you rebelled against God and are headed for eternal damnation?

(Some insights taken from Barnes' Notes)