I will paste a commentary from Matthew Henry on your verse. I will also put the page in my "source" box for further reading and follow-up.
Some think this refers to the severe censures they passed upon those who had already gone into captivity (who were humbled under their affliction, by which their hearts were made sad), and the commendations they gave to those who rebelled against the king of Babylon, who were hardened in their impieties, by which their hands were strengthened; or by their polluting the name of God they saddened the hearts of good people who have a value and veneration for the word of God, and confirmed atheists and infidels in their contempt of divine revelation and furnished them with arguments against it. Note, Those have a great deal to answer for who grieve the spirits, and weaken the hands, of good people, and who gratify the lusts of sinners, and animate them in their opposition to God and religion. Nor can any thing strengthen the hands of sinners more than to tell them that they may be saved in their sins without repentance, or that there may be repentance though they do not return from their wicked ways. 5. They mimicked the true prophets, by giving signs for the illustrating of their false predictions (as Hananiah did, Jer. 28:10), and they were signs agreeable to their sex; they sewed little pillows to the people’s arm-holes, to signify that they might be easy and repose themselves, and needed not be disquieted with the apprehensions of trouble approaching. And they made kerchiefs upon the head of every stature, of persons of every age, young and old, distinguishable by their stature, v. 18. These kerchiefs were badges of liberty or triumph, intimating that they should not only be delivered from the Chaldeans, but be victorious over them. Some think these were some superstitious rites which they used with those to whom they delivered their divinations, preparing them for the reception of them by putting enchanted pillows under their arms and handkerchiefs on their heads, to raise their fancies and their expectations of something great. Or perhaps the expressions are figurative: they did all they could to make people secure, which is signified by laying them easy, and to make people proud, which is signified by dressing them fine with handkerchiefs, perhaps laid or embroidered on their heads.