From this ayat it becomes apparent that toogether with striving to attain spiritual purification it is also essential to attain the Graces and Mercy of Allah Rabbul izzat. We have to constantly entreat him to include us amongst those whome he has purified.
Movlana Rumi writes:
O Allah! If a thousand chains of carnal desires and satanaic deceptions have shackled our feet, we have nothing to fear if your Graces are upon us.”