For my days are consumed like smoke, and my bones are burned as an hearth.
An hearth — An hearth is heated or burnt by the coals which are laid upon it.
 By reason of the voice of my groaning my bones cleave to my skin.
Skin — My flesh being quite consumed.
 I am like a pelican of the wilderness: I am like an owl of the desert.
A pelican — Is a solitary and mournful bird.
 For I have eaten ashes like bread, and mingled my drink with weeping,
Bread — The sense is, dust and ashes are as familiar to me as the eating of my bread; I cover my head with them; I sit, yea, lie down in them, as mourners often did.
 Because of thine indignation and thy wrath: for thou hast lifted me up, and cast me down.
Lifted me — As a man lifts up a thing as high as he can, that he may cast it to the ground with greater force.
 But thou, O LORD, shalt endure for ever; and thy remembrance unto all generations.
Remembrance — Thy name, Jehovah, which is called by this very word, God's remembrance, or memorial, and that unto all generations, Exodus 3:15.
 Thou shalt arise, and have mercy upon Zion: for the time to favour her, yea, the set time, is come.
The set time — The end of those seventy years which thou hast fixed.
 This shall be written for the generation to come: and the people which shall be created shall praise the LORD.
This — This wonderful deliverance shall be carefully recorded by thy people.
 For he hath looked down from the height of his sanctuary; from heaven did the LORD behold the earth;
Looked — From heaven.
 To hear the groaning of the prisoner; to loose those that are appointed to death;
To loose — To release his poor captives out of Babylon, and from the chains of sin and eternal destruction.
 To declare the name of the LORD in Zion, and his praise in Jerusalem;
To declare — That they might publish the name and praises of God in his church.
 When the people are gathered together, and the kingdoms, to serve the LORD.
When — When the Gentiles shall gather themselves to the Jews, and join with them in the worship of the true God.
 He weakened my strength in the way; he shortened my days.
He — God.
The way — In the midst of the course of our lives. Some think the psalmist here speaks of the whole commonwealth as of one man, and of its continuance, as of the life of one man.
 I said, O my God, take me not away in the midst of my days: thy years are throughout all generations.
I said — Do not wholly destroy thy people Israel.
In the midst — Before they come to a full possession of thy promises and especially of that fundamental promise of the Messiah.
Thy years — Though we die, yet thou art the everlasting God.
 They shall perish, but thou shalt endure: yea, all of them shall wax old like a garment; as a vesture shalt thou change them, and they shall be changed:
Perish — As to their present nature and use.
 The children of thy servants shall continue, and their seed shall be established before thee.
Continue — Though the heavens and earth perish, yet we rest assured that our children, and their children after them, shall enjoy an happy restitution to, and settlement in their own land.