His Final Praise And Thanksgiving Because He Had Been Delivered (Psalms 30:11-12).
‘You have turned for me my mourning into dancing,
You have loosed my sackcloth, and girded me with gladness,
But then all had changed. The sickness had left him, and he was conscious of a new beginning. His mourning had been turned into dancing, which was certainly not the behaviour of a sickly man. He had been restored to strength. And God had removed his sackcloth, the sign of his mourning, and had instead girded him with gladness. Compare Isaiah 61:1-3 where the coming of the Anointed Prophet would also introduce such joy and gladness. The Good News of God always brings gladness.
To the end that my glory may sing praise to you and not be silent.
O YHWH my God, I will give thanks to you for ever.
And the resulting end of his experience will be that in his own glory as the king, which was the result of God's goodness to him, he will sing praises to YHWH, and will not be silent. As far as he is now concerned YHWH is his God, and he will give thanks to Him for ever.