My heart greatly rejoices, says Psalm 28:7, but why?

Today’s Therefore:

“Therefore my heart greatly rejoiceth” (Psalm 28:7).

Why for is it there for?

When my heart is overwhelmed, I cry out. Or cry? And. Maybe.
From the end of the earth will I cry unto thee,
when my heart is overwhelmed:
lead me to the rock that is higher than I.

-Psalm 61:2