John Calvin Commentary Isaiah 15:3

"In their streets they gird themselves with sackcloth; on their housetops, and in their broad places, every one waileth, weeping abundantly." — Isaiah 15:3 (ASV)

In his streets. He continues with the same subject, describing more fully the signs of mourning, in which Eastern nations are more profuse than others. For, having quicker understanding and keener feelings, they express their emotions by outward signs more than others do, who, being slower to comprehend, are also slower in movement and gesture. It was undoubtedly a fault in them that they indulged in so many ceremonies and gesticulations; but the Prophet spoke of these practices as known and common, only to describe the grief that would follow the desolation of that country.

Every one shall howl and descend to weeping. He added this description with good reason, for we are never moved by predictions unless the Lord places them, so to speak, before our eyes. So that the Jews would not think that these matters might be dismissed lightly, when he described that destruction, he also decided to mention mourning, weeping, and howling, so that they might almost see with their own eyes those events that appear incredible. For the Moabites were at that time in a state of profound peace, and believers had an even greater need to be confirmed, so that they would not doubt this prophecy. By this means, he points out the despair to which unbelievers are liable in adversity, because the support on which they rely is insecure.