בְּכָל־עֵ֕ת יִהְי֥וּ בְגָדֶ֖יךָ לְבָנִ֑ים וְשֶׁ֖מֶן עַל־רֹאשְׁךָ֥ אַל־יֶחְסָֽר׃
Lascia che le tue vesti siano sempre bianche; E lascia che alla tua testa non manchi olio.
Zohar
And when his eyes are there, he should know that that flame that is lit above his head needs oil, for the body of a person is itself a wick, and a flame is lit above. And King Solomon shouted and said,"do not lack oil upon your head" (Ecclesiastes 9:8). For the flame that is above his head requires oil, and this represents good deeds. And for this reason, the wise person's eyes are above their head, and not in another place.