According to the author of 2 Samuel, this verse talks about a wise lady who reminds people that long ago, everyone knew they could ask for advice in the town of Abel to solve their problems. It's like when you know a special place where you can always go to find answers and make things better.
2 Samuel 20:18: Then she spake, saying, They were wont to speak in old time, saying, They shall surely ask [counsel] at Abel: and so they ended [the matter]. [They were...: or, They plainly spake in the beginning, saying, Surely they will ask of Abel, and so make an end]
While 2 Samuel 20:18 highlights the wisdom in listening to advice, Proverbs 26:4 advises not to engage with the foolish, which could imply ignoring certain types of advice or counsel that contradicts with listening.
Proverbs 26:4: Answer not a fool according to his folly, lest thou also be like unto him.