My days are consumed like smoke - He represents himself (for the psalmist speaks in the name of the people) under the notion of a pile of combustible matter, placed upon a fire, which soon consumes it; part flying away in smoke, and the residue lying on the hearth in the form of charred coal and ashes. The Chaldeans were the fire, and the captive Jews the fuel, thus converted into smoke and ashes.
For my days are consumed like smoke - Margin, “into smoke.” Literally, “in smoke.” That is, They vanish as smoke; they pass away and become nothing; they are spent in affliction, and seem to accomplish nothing. The idea is, that in his affliction he seemed to accomplish none of the ends of life. His life seemed to be wasted. This is often the feeling in trial: and yet in trial a man may be more useful, he may do more to accomplish the real ends of life, he may do more to illustrate the power and excellence of religion, than he ever did in the days of prosperity.
And my bones are burned as an hearth - Or rather, as faggots or fuel. Literally, “They are burned as a burning.” The idea is, that in his troubles, his very bones, the most solid and substantial part of himself, seemed to be consumed and to waste away. See the notes at Psalm 31:10.