Surely he will pity his city and free his people.

Psalm 102
For my days vanish like smoke; my bones burn like glowing embers. My heart is blighted and withered like grass; I forget to eat my food. My days are like the evening shadow; I wither away like grass.
But you, O Lord, sit enthroned forever; your renown endures through all generations.
The Lord will rebuild Zion and appear in his glory, He will respond to the prayer of the destitute; he will not despise their plea.
In the course of my life he broke my strength; he cut short my days. So I said: Do not take me away, O my God, in the midst of my days; your years go on through all generations.
Heaven and earth will perish, but you remain; they will all wear out like a garment. Like clothing you will change them and they will be discarded. But you remain the same, and your years will never end.
The psalmist is a young man, wearied by suffering. He pours out all his feelings to God.
v1-11 describe his suffering: ill in body, sick at heart, taunted by enemies. cast off by God. His life is slipping away, but God is not subject to time.
V12-22 may be a hymn the psalmist has included within his prayer. God is Sovereign for ever. Surely he will pity his city and free his people.
V 23-28 revert to the personal. Surely God will answer the psalmist's prayer.
Why?
Pray to the Lord what psalmist is suffering and asked the Lord help him.
Among so much pain and he still believe that the Lord is the sovereign God, he believed the Lord will not forsake him, still listening to his prayer.
Do not take me away in the midst of my days: for he is young.
His day like smoke and the evening shadow means it will soon disappear.
God's year go on through all generations. God is remain even the world is changed like garment.
How?
Surely he will pity his city and free his people. God is my savior and my fortress.