Brahmayacanasutta 1.8

1.8

Ahañceva kho pana dhammaṃ deseyyaṃ; pare ca me na ājāneyyuṃ; so mamassa kilamatho, sā mamassa vihesā”ti.

And if I were to teach this principle, others might not understand me, which would be wearying and troublesome for me.”