“having their beards shaved.” Easterners were very proud and protective of their beards, and shaving them off was a demonstration of great commitment, in this case showing the great sorrow they had. In 2 Samuel 10:4-5, the king of Ammon took the emissaries that had come from David and shaved off half their beards, and the men were so embarrassed that David advised them to stay away from Jerusalem until their beards had grown back.
A similar sign of mourning to shaving the beard was shaving the head. Verses that mention shaving the head in mourning for the dead include Isaiah 15:2; 22:12; Jeremiah 16:6; 48:37; Ezekiel 7:18; and Micah 1:16. Other signs of mourning include putting on sackcloth (cp. Jer. 48:37), having a time of silence (Jer. 47:5), and cutting oneself. It was also customary for people to bring food and have a mourning feast (Jer. 16:5-8).
“having cut themselves.” God made humans in His own image, and we are “fearfully and wonderfully made” (or “remarkably and wonderfully made” HCSB; Ps. 139:14). Nevertheless, the Devil has been successful in getting people to cut and burn themselves for a number of different reasons. Here in Jeremiah, Israelites have slashed themselves as part of their mourning for the dead. Cutting oneself was a pagan custom that was done as part of mourning for the dead. It became a practice of some Israelites as they began to follow some of the pagan customs from the culture around them, particularly as they were influenced by demons (Jer. 16:6; 41:5; 47:5; 48:37), but God never wanted people to mourn that way and forbade it in the Law of Moses: “do not cut yourselves…for the dead” (Deut. 14:1). In that culture, cutting oneself not only needlessly harmed the person, and from the Devil’s point of view defaced God’s wonderful creation, but it was a genuine danger because the people had no effective way to fight infection if the wound should become infected. Thus every cut was a very real danger to the person. Of course, the pain and suffering of the cut was supposed to show how deeply the person cared for the one who had died, but that is a false and demonic display of sincerity. God never wants or requires it of people.
The fact that the Jews would cut themselves for the dead in spite of it being prohibited by the Law shows how deeply the pagan religions had penetrated the culture in Judah at this time. Jeremiah 2:8 gives a pretty graphic picture of the state of things in Judah: the priests had stopped asking about Yahweh’s involvement, the rulers broke the Law, and the prophets prophesied by Baal, and followed idols. [For more on cutting and self-mutilation, see commentary on 1 Kings 18:28. For the custom of shaving the head for the dead and some other customs associated with death, see commentary on Jer. 47:5].