Verse 5 is in the middle of a short 8 verse Psalm. A song that would have been sung as they climbed the hill to Jerusalem and worship at the Temple.
What inspired the writer of this song? Verse 1 tells that he cried out from the deep. Some translations use the phrase “from the deep water”. The psalmist could have felt that he was about to die! He then cried out to God with everything in him. This reminds me of famous Old Testament person. Jonah cries out to God in a similar way in Jonah 2.
Most Americans today have never faced such life threatening situations! Please read the entire Psalm below and then go read Jonah 2 to get som real perspective in totally relying on God.
A song of ascents.
 From the deep water I cry out to you, O LORD.
 O Lord, listen to me!
Pay attention to my plea for mercy!
 If you, O LORD, were to keep track of sins,
O Lord, who could stand before you?
 But you are willing to forgive,
so that you might be honored.
 I rely on the LORD,
I rely on him with my whole being;
I wait for his assuring word.
 I yearn for the Lord,
more than watchmen do for the morning,
yes, more than watchmen do for the morning.
 O Israel, hope in the LORD,
for the LORD exhibits loyal love,
and is more than willing to deliver.
 He will deliver Israel
from all the consequences of their sins.