Basic translation of Biur Hagra, Mishlei 6:9:
“How long will you lie down, lazy one?” relates to what Chazal taught: “If I am not for myself, who will be for me? And if not now, when?” These correspond to two things: wisdom and action.
“If I am not for myself, who will be for me?” refers to wisdom, meaning that if I do not think on my own behalf, who will think for me? “And if not now, when?” refers to action, that if I do not act now, when will I act?
They said “now” and did not say “today” – meaning that even on that very same day, if I do not act now, when will I?
Same here: “How long will you lie down, lazy one?” refers to the absence of action, for when one is lying down, he does nothing at all, though he can still think. “When will you arise from your sleep?” refers to the absence of thought, meaning: if you are not acting now, when will you act? And if you are not thinking for yourself, who will think in your stead?