Therefore, come and see how grateful we should be to our teachers, who impart us their sacred Lights and dedicate their souls to do good to our souls. They stand in the middle between the path of harsh torments and the path of repentance. They save us from the netherworld, which is harder than death, and accustom us to reach the heavenly pleasures, the sublime gentleness and the pleasantness that is our share, ready and waiting for us from the very beginning, as we have said above. Each of them operates in his generation, according to the power of his teaching and attainment.
– Baal HaSulam, “Introduction to the Book, Panim Meirot uMasbirot,” Item 8