Then she spake, saying, {l} They were wont to speak in old time, saying, They shall surely ask counsel at Abel: and so they ended the matter.

(l) She shows that the old custom was not to destroy a city before peace was offered, De 20:10,11.

Wesley's Notes

20:18 Ask counsel - This city which thou art about to destroy, is no mean and contemptible one, but so honourable and considerable for its wisdom, that when any differences arose among any of the neighbours, they used proverbially to say, We will ask the opinion and advice as the men of Abel about it, and we will stand to their arbitration; and so all parties were satisfied, and disputes ended.

King James Translators' Notes

They were...: or, They plainly spoke in the beginning, saying, Surely they will ask of Abel, and so make and end

Jamieson-Fausset-Brown Bible Commentary

18-20. They were wont to speak in old time-The translation of the Margin gives a better meaning, which is to this effect: When the people saw thee lay siege to Abel, they said, Surely he will ask if we will have peace, for the law (De 20:10) prescribes that he should offer peace to strangers, much more then to Israelitish cities; and if he do this, we shall soon bring things to an amicable agreement, for we are a peaceable people. The answer of Joab brings out the character of that ruthless veteran as a patriot at heart, who, on securing the author of this insurrection, was ready to put a stop to further bloodshed and release the peaceable inhabitants from all molestation.

Matthew Henry's Concise Commentary

20:14-22 Justly is that place attacked, which dares to harbour a traitor; nor will the heart fare better which indulges rebellious lusts, that will not have Christ to reign over them. A discreet woman, by her prudent management, satisfied Joab, and yet saved the city. Wisdom is not confined to rank or sex; it consists not in deep knowledge; but in understanding how to act as matters arise, that troubles may be turned away and benefits secured. A great deal of mischief would be prevented, if contending parties would understand one another. Let both sides be undeceived. The single condition of peace is, the surrender of the traitor. It is so in God's dealing with the soul, when besieged by conviction and distress; sin is the traitor; the beloved lust is the rebel: part with that, cast away the transgression, and all shall be well. There is no peace on any other terms.