धर्माथौ यत्र न स्यातां शुश्रूषावाऽपि तद्विधा ।
तत्र विद्या न वक्तव्या शुभं बीजमिवोषरे ॥
One must not teach a person anything if he does not have any one of the following qualities: follows dharma, is wealthy, has a mindset for service. Without any of these qualities, teaching him is equivalent to sowing seeds in a barren land.
- Manu Smriti