Your hearts must be pure

I am going away, but you must arise to serve the Word of God. Your hearts must be pure and your intentions sincere in order that you may become recipients of the divine bestowals. Consider that although the sun shines equally upon all things, yet in the clear mirror its reflection is most brilliant and not in the black stone. This great effulgence and heat have been produced by the crystal clearness of the glass. If there were no clearness and purity, these effects would not be witnessed. Should rain fall upon salty, stony earth, it will never have effect; but when it falls upon good pure soil, green and verdant growth follows, and fruits are produced.
This is the day when pure hearts have a portion of the everlasting bounties and sanctified souls are being illumined by the eternal manifestations.

`Abdu'l-Bahá:The Promulgation of Universal Peace