Talk not much with a fool, and go not to him that hath no understanding: beware of him, lest thou have trouble, and thou shalt never be defiled with his fooleries: depart from him, and thou shalt find rest, and never be disquieted with madness.

[μετὰ ἄφρονος μὴ πληθύνῃς λόγον
καὶ πρὸς ἀσύνετον μὴ πορεύου·
φύλαξαι ἀπ᾽ αὐτοῦ, ἵνα μὴ κόπον ἔχῃς
καὶ οὐ μὴ μολυνθῇς ἐν τῷ ἐντιναγμῷ αὐτοῦ·
ἔκκλινον ἀπ᾽ αὐτοῦ καὶ εὑρήσεις ἀνάπαυσιν
καὶ οὐ μὴ ἀκηδιάσῃς ἐν τῇ ἀπονοίᾳ αὐτοῦ.]

The Bible (The Old Testament) (14th - 2nd C BC) Judeo-Christian sacred scripture [Tanakh, Hebrew Bible], incl. the Apocrypha (Deuterocanonicals)

Book 22b. Sirach (Ecclesiasticus) 22:13 (Sir 22:13) [tr. KJV (1611)]
    (Source)

Some translations note that the Septuagent includes, after the first sentence, e.g., "When people are senseless, they will bring everything of yours to nothing" or "For being without sense he will despise everything about you."

More on the history and acceptance of this Apocryphal book here and here.

(Source (Greek)). Alternate translations:

Talk not much with a fool, and go not with him that hath no sense.
Keep thyself from him, that thou mayst not have trouble, and thou shalt not be defiled with his sin.
Turn away from him, and thou shalt find rest, and shalt not be wearied out with his folly.
[tr. DRA (1899), 22:14-16]

Do not waste many words on a stupid man,
do not go near a dolt.
Beware of him, or he will give you trouble;
and will leave you soiled by contact with him.
Avoid him, and you will find rest
and not be exasperated by his folly.
[tr. JB (1966)]

Do not waste many words on the stupid,
do not go near a dolt.
Beware of him, or you will have trouble
and be soiled by contact with him;
keep away from him, and you will have peace of mind
and not be exasperated by his folly.
[tr. NJB (1985)]

Don't visit stupid people or spend a lot of time talking with them. Avoid them; then they can't contaminate you, and you can live in peace without being troubled or worn down by their foolishness.
[tr. GNT (1992 ed.)]

Don’t talk a lot with fools,
and don’t go to the unintelligent.
Be on guard against them
so that you don’t have trouble
and don’t get dirty
when they shake themselves off.
Stay away from them
and you will find rest,
and their senselessness
class="tab">won’t make you weary.[tr. CEB (2011)]

Do not talk much with senseless people
or visit unintelligent people.
Stay clear of them, or you may have trouble
and be spattered when they shake themselves off.
Avoid them and you will find rest,
and you will never be wearied by their lack of sense.
[tr. NRSV (2021 ed.)]