Translation
If the snake bites when it is not whispered to (charmed),
Go to footnote numberthere is no profit for the owner of the tongue
Go to footnote numberi.e. the one doing the whispering.
Paraphrase
If you are doing a dangerous thing and things don’t work out as you had hoped, you may get no profit at all for your efforts. Take the dangers into account before you do any task.
Footnotes
1: “not charmed”
The verb comes from a root meaning “the tongue” and means “to whisper.” When one is whispering to a snake, it is called snake charming. In general this phrase is saying “when the snake is not charmed,” but in relation to time it can mean “before,” as in “before it is charmed.” Either way the idea is that the snake is not supposed to bite the charmer, and if it does, for whatever reason, he gets no profit. Be careful when you decide to whisper to a snake, it might “whisper” at you first.
2: “owner of the tongue”
Solomon is talking about the charmer here, even though both the charmer and the snake have tongues. This word and the one used earlier meaning “whisper or charm” and are from the same root, meaning “tongue.” Solomon chose a strange way to say it in order to make his reader think about something. By saying “the owner of the tongue,” he wanted his reader to ask, “which one? – they both have tongues.” By saying it this way he was calling into question the wisdom of even getting into a line of work which so easily can be turned against the person involved.