PSALM 39:5,6

5: Indeed,You have made my days as handbreadths,

And my age is as nothing before You;

Certainly every man at his best state is but vapor. Selah

6: Surely every man walks, about like a shadow;

*handbreadths-width of the palm of the hand.

*Selah-(1) a word which appears in the Psalms 71 times.

it's probably a musical note, or pause.