Different Kinds of Purity - 6th Purity

The sixth purity is Purity by knowledge and vision of the path  (patipada- nana-dassana-visuddhi).
When the imperfections of insight have been overcome, panna becomes more accomplished as the development of satipatthana continues, and then there is purity by knowledge and vision of the path. While the person who develops insight is now free from the imperfections of insight, there is this purity from the fourth stage of insight on, which is knowledge of the arising and falling away of realities, and it continues up to adaptation knowledge (anuloma nana). Adaptation knowledge are the three moments of citta arising in the magga-víthi: parikamma or preparatory citta, upacara or access and anuloma or adaptation.