Rogasutta 2.6

2.6

So saṅkhāya kulāni upasaṅkamati, saṅkhāya nisīdati, saṅkhāya dhammaṃ bhāsati, saṅkhāya uccārapassāvaṃ sandhāreti.

They have an ulterior motive when they visit families. They have an ulterior motive when they sit down, when they speak on Dhamma, and even when they hold it in when they need to go to the toilet.