His Prayer For Deliverance (Psalms 30:8-10).
I cried to you, O YHWH,
And to YHWH I made supplication,
What profit is there in my blood,
When I go down to the pit?
Will the dust praise you?
Will it declare your truth?
Hear, O YHWH, and have mercy on me,
YHWH, be you my helper.
So the Psalmist's cry reaches up to God. It is possible that we should see the initial verb as a historic present, making the picture vivid. ‘I am crying to you, O YHWH'. But the main point is that his plea is to YHWH.
In the depths of his illness his argument is simply that if he dies he will be able to praise YHWH no more. It is the prayer of someone very ill who has at this moment little time for theology. He is down to the basic practicalities. ‘In my blood' simply means ‘in my death'. The point is that in the grave he will not be able to praise YHWH, nor will he be able to testify of Him.