Truly, it is not easy to teach the Dharma to others.
In teaching the Dharma to others, establish well five things, and then teach.
Teach the Dharma to others, thinking:
‘I will speak the Dharma in a gradual way;
I will speak with good in mind;
I will speak with kindness;
I will not speak as a means of gain;
I will speak neither to my own harm, not to the harm of others.’
– The Buddha (Anguttara Nikaya: A,III:184)