The ásavas are destroyed only by self training, not by merely wishing for their destruction. A hen may wish for her chicks to break through their eggs with foot, or claw, or mouth, or beak, but they will not do so till they are fully warmed, fully brooded over by the hen. When they are ready to break through, they will do so, irrespective of the hen's wish. A carpenter knows that his adze handle has worn away, not by looking at the finger marks on the handle, but just by its wearing away.
A seagoing vessel, stranded without water and beaten on by wind and sun, will fall to pieces easily and without effort. So will the ásavas in a monk who dwells attentive to self training. S.iii.152f.; cp. A.iv.126f.