Psalms 26:6

I will wash my hands in innocency,

So will I compass your altar, O YHWH.

Furthermore when he comes to stand around the altar with those who offer sacrifices, he prepares himself by making himself ‘innocent' as a result of having had his sin dealt with by seeking God and putting it away from him. He has heeded the words of Isaiah, ‘Wash yourselves, make you clean, put away the evil of your doings from before my eyes' (Isaiah 1:16). Now therefore he only has to ‘wash his hands' that is deal with current sins. (We can compare Jesus' words, ‘he who has been bathed needs only to was his feet' - John 13:10). The washing of the hands has in mind the fact that the priests had to wash their hands and feet regularly as they operated between the altar and the holy place lest they die (Exodus 30:17), because of the defilement of earth contacted during that short walk, but the lack of mention of the feet here makes clear that this is intended to be seen as metaphorical. Compare Psalms 73:13 where washing the hands in innocency parallels the cleansing of the heart. Before coming into God's presence in this way he has prepared his heart.