A person who knows himself need know nothing more, nothing else

आनृशंस्यं परो धर्मः क्षमा च परमं बलम्।

आत्मज्ञानं परं ज्ञानं न सत्याद्विद्यते परम्॥

इन्दिश्चे स्प्रूचे ३७०८ महाभारते

ānṛśaṁsyaṁ paro dharmaḥ kṣamā ca paramaṁ balam|

ātmajñānaṁ paraṁ jñānaṁ na satyādvidyate param||

indiśce sprūce 3708 mahābhārate

The greatest, most supreme virtue, a characteristic trait a person should possess is the capacity to be soft and mild, not cruel and hard-hitting, not being too demanding and crass towards others or even towards himself

Patience, forbearance, capacity to forgive, a mind to understand and apprecitate things from the viewpoint of thers too, is the greatest strength one can possess. If one has that capacity then nothing physical or terrestrial can really defeat him.

If one strives to delve deep into Himself, His inner core and attempts to understand what he and his existence really mean, really mean beyond the apparent manifestations, and manages to gain some insights in that direction, then that is the supreme knowledge he can possess. 

A person who knows himself need know nothing more, nothing else.

And above all these, the Supreme thing, the supreme guiding star, the supreme thing beyond which there can be nothing… is truth, adherence to truth.

Indeed a great summing up from the epic Mahabharatham

आनृशंस्यं mildness, lack of cruelt परं the best, the supreme, the most desirable धर्मः virtue, the rule of conduct भवतिis क्षमा patience, forbearance, capacity to tolerate and forgive एव alone परमं the hightest बलं strength वर्तते is

आत्मज्ञानं knowledge of the inner self, inner core एव is indeed परं suprem ज्ञानं इति बोधितव्यं knowledge, it should be understood सत्यात् from, in comparison to truth परं above, superior to किमपि nothing whatever न विद्यते does not exist