The last words of this verse in our Greek source are:
ουκ αφέξεσθε απ' αυτού
Literally: ‘not you-all-keep-away away-from him’.
The word for ‘you-all-keep-away’ (αφέξεσθε) is a conjugated form of the verb ᾰ̓πέχω (apékhō) which means ‘to avoid’. This specific conjugation is in the future tense (so it is giving advice as to what ought to be done when it eventually happens), it’s the second person plural (so it’s speaking to all of us), and it’s the middle indicative (telling you what to do). Therefore, it commands everyone to stay away.
As for the word ‘not’ which appears beforehand, it’s a double negative, which is frequently used in Ancient Greek for emphasis. Therefore, “don’t have anything to do with him” more accurately represents the Greek source in modern American English.
At first glance, the Hebrew text appears to say something quite different: “thou shalt not be afraid of him”. However, the Greek and Hebrew may have originally had the same meaning to ancient readers.
You see, in Hebrew the verb meaning to be afraid can also mean ‘to stand in awe’, and to ‘sojourn’. In modern parlance we might say that it describes being so impressed by someone that we ‘follow’ them. So at the time the Greek Septuagint was translated, the Jews clearly understood that (in the context) it was saying that the Jews should not be impressed by and follow false prophets, in other words, they should not ‘fear’ them.
So the Greek and Hebrew are actually in agreement, and the Greek translation sheds light on how the Hebrew was understood 2,300 years ago.