"And Moses went up to God" (Exodus 19:3). Rebbe Elimelech of Lizhensk, commenting on Parashat Yitro, draws a distinction between two kinds of righteous people—and explains why Moses stands above them both.
The great tzaddik (a righteous person) is called by the name "Moses." This level has something the other righteous lack: the ability to ascend to the upper worlds. "And God called him"—the word "called" implies affection. God summons this highest-level tzaddik with love.
Then come two categories of recipients. "Thus shall you say to the house of Jacob"—these are the tzaddikim (the righteous) who have not yet reached Moses's level. Their responsibility is to repair the Shechinah, the Divine Presence, denoted by the word "thus" (koh). "And declare to the children of Israel"—these are the fully realized tzaddikim, known by the exalted name Israel, whose work is harder, "as difficult as tendons."
Rebbe Elimelech reads the same verse a second way. The word "thus" (koh) contains all blessings—"Thus shall you bless," "Thus shall be your seed." Most of the world needs material sustenance. So God tells Moses: for the house of Jacob, channel the energy of koh—physical blessing, monetary abundance, material well-being.
"And tell the children of Israel"—for the great ones, the channel is different. Telling (hagadah) implies continuation, an ongoing flow. What flows to them is not material wealth but higher light—a great love and awe from the upper worlds poured into their hearts, fueling the spiritual work that sustains everything else.