Speak, young man, if there be need of you: and yet scarcely when you are twice asked.
LXX
Sirach 32:7
The sacrifice of a just man is acceptable, and the memorial thereof shall never be forgotten.
Parallel Translations
Speak, young man, if there be need of thee: and yet scarcely when thou art twice asked.
Speak, young man, if you are obliged to, but no more than twice, and only if asked.