Full Idea
The chief good is unity, which is known by several names, for at one time people call it prudence, at another time God, at another intellect, and so on.
Gist of Idea
The chief good is unity, sometimes seen as prudence, or God, or intellect
Source
Eucleides (fragments/reports [c.410 BCE]), quoted by Diogenes Laertius - Lives of Eminent Philosophers 02.9.2
Book Reference
Diogenes Laertius: 'Diogenes Laertius', ed/tr. Yonge,C.D. [Henry G. Bohn 1853], p.97
A Reaction
So the chief good is what unites and focuses our moral actions. Kant calls that 'the will'.