Yosay ben Yochanan of Jerusalem said, "Let your house be wide open to guests [in Hebrew, 'revacha']; treat the poor as members of your household…." (Avot 1:5)

"Let your house" refers to the Torah, which is called "a house". May that be open to [the word] "revacha", whose letters can be rearranged to spell "Ruach hei". "Ruach" implies Zeir Anpin, and "hei" implies Malchut. This is to teach us that learning Torah for the sake of [serving] G‑d means in order to unite Zeir Anpin [the masculine principle] with Nukva [or Malchut, the feminine principle], to complete the Supernal Tree and to erect the fallen Tabernacle of David.