The Talmud in Masechet Yoma 53b discusses the route that the Kohen Gadol took when he entered the Holy of Holies on Yom Kippur. There were actually two curtains in the second Temple and the High Priest walked in between them as he entered. The interesting point that is emphasized by the Gemara is that the Kohen Gadol had to retrace his steps and walk backwards as he left the Holy of Holies. It would not be respectful for him to turn his back on such a holy place. This is the reason why we have the custom of taking leave of the Kotel by walking backwards and not turning our backs to a sacred place. The Talmud adds that we are to apply this as well when we take leave of being in the presence of a Tzaddik or great Torah scroll. We don't turn our face to him but we take leave by walking backwards. Rav Elazar Abuchatzeira זצ״ל, whose fifth Yahrtzeit is today was such a Tzaddik and scholar who deserved this kind of reverence and respect. May his memory be for a blessing.