אֵין הַבּוֹר מִתְמַלֵּא מֵחֻלְיָתוֹ

ביטוי (אנגלית)

The cistern is not filled from its own hole

הגדרה (אנגלית)

A water cistern does not fill merely from the opening at its top, but from the underground waters flowing into it. Figuratively: Every person needs assistance. The little that one has is not enough; it must be developed.

(David was standing and studying Torah... The sages of Israel entered before him. They said: Our lord the king, your people Israel need sustenance! He said to them: Go, earn a living from one another. They said to him: 'A handful does not satisfy the lion, and the cistern is not filled from its own hole.' - Sanhedrin 16a)