תּלמוד אויף תהילים 147:20

Rabbi Ami said, "We only teach the secrets of Torah to one who has five qualities: 'A leader (alt. a captain) of fifty, favored, advice-giving, wise of the deaf, and clever of secrets [these last two may mean someone who can infer things without being told].'" And Rabbi Ami said, "We don't teach Torah to idol-worshipers, as it is said, 'He did not do such to all nations, and laws He did not cause them to know (Psalms 147:20).'"