That I may make the voice of thanksgiving to be heard,
And tell of all your wondrous works.
And the result of his coming before YHWH fully clean will be that his voice will ring out in thanksgiving, and he will proclaim all that the Lord has done for him.
Connecting with the previous verse this verse may suggest that he sees himself as there because of a fervent desire to offer a thanksgiving offering which would then be partaken of in his home or palace where he would tell his guests the reason for his gratitude to YHWH, recounting the wonderful things that He had done for him. But whether that is so or not, it is a reminder that all our worship should finally result in thanksgiving and testimony.