Musar על זכריה 3:4

And Scripture states (Ibid. 49): "And you shall make yourselves holy, and you shall be holy, concerning which Chazal say (Yoma 39a): "If a man sanctifies himself a little, they sanctify him a lot; from below, they sanctify him from above; in this world, they sanctify him in the world to come." And now, everything is plainly understood. The Holy One Blessed be He, being the source of the good and of chesed— when a man suppresses his yetzer and draws himself a little to the side of holiness— the Holy One Blessed be He confers upon him "a lot" of holiness, a "full handful." As Chazal say (Shir Hashirim Rabbah 5): "The Holy One Blessed be He said: "Open before Me an opening like that of a [fine] needle, and I will open for you an opening like that of an entrance hall." "from below, they sanctify him from above." That is, holiness is drawn down from above upon the source of his soul. "in this world, he is sanctified in the world to come." That is, when he ascends above and has to stand before the throne of the L-rd, he is clothed in vestments of the majesty and glory of sanctity (as it is written of Yehoshua ben Yehotzadak (Zechariah 3:4): "And I have dressed you with festive garments.")