What is the Summary Advice of the Buddha?

To Answer this question; as arule of practice ;the Buddha taugh; "Avoid evil; do good ;purify the mind ." Those three together are called the "Ovada patimokkha ;" meaning the "summary of all exhortations.
Avoid evil; do good; purify the mind . Avoiding evil and doing good need no explaining; but making the mind pure isn't as obvious.
If one goes about grasping and clinging even to goodness; the mind develops impurities: fear of not receiving good ; fear of beeing deprived of existing good; anxiety; worry; and attaching to this and that as "mine".All of these produce suffering.
Even though we may have successfully avoided evil and done good; we still must know how to render the mind free.Do not grasp at or cling to anything as being a self or as belonging to a self. Otherwise it will be misery; it will be misery; it will be a heavy burden and it will be suffering (dukkha).
In other words; grasping and clinging; like carrying something along with one all the time; is a heavy weight and a burden of suffering .Even a load of precious gems carried on the shoulders or head is just as heavy as a load of rocks.So don't carry rocks or gems(dukkha).Put them aside.
Don't let there be any weight on your head ( which here means the mind) .This is what is meant by "purify the mind".
To sum up the question:

• Don't do evil.
  *Do only good deed.
  *Keep the mind purified.
  *This is the summary advice of the Buddha.

Cridit photo by google.