Plutarch De amicorum multitudine 4

[4] We ought therefore not to accept readily chance acquaintances, or attach ourselves to them, nor ought we to make friends of those who seek after us, but rather we should seek after those who are worthy of friendship. For one should by no means take what can be easily taken. In fact we step over or thrust aside bramble and brier, which seize hold upon us, and make our way onward to the olive and the vine. ¹ Thus it is always an excellent thing not to make an intimate acquaintance of the man who is ready with his embraces, but rather, of our own motion, to embrace those of whom we approve as worthy of our attention and useful to us.

[4] Therefore it highly concerns us not to be too rash in fastening on the next that may accidentally offer, nor presently to affect every one that pretends to be fond of our friendship. Let the search rather begin on our own part, and our choice fix on those who approve themselves really worthy of our respect. What is cheap and with ease obtained is below our notice; and we trample under foot bushes and brambles that readily catch hold of us, while we diligently clear our way to the vine and olive; so it is always best not to admit to our familiarity persons who officiously stick and twist themselves about us, but we ought rather of our own accord to court the friendship of those who are worthy of our regard, and who prove advantageous to ourselves.