This Psalm finds its surprising historic and musical situation in the hymnal of Jeduthun. I Chron 16:41-43 & II Chron 5:12 remind us of the worship leading commission represented in this title.
Jeduthun and company were called to glorify the Lord in song specifically extolling the steadfast love of the Lord. The staggering riches implied in such a theme are demonstrated in this song. Ps 39 provides a lament, an elegy of chiastic paradox as ideas are symmetrically organized in the shape of an hourglass – another helpful picture to “...let us know how fleeting we are” (v:4).