John Trapp on 1 Thessalonians 5:16

Verſe 16. Rejoyce evermore] A duty much preſſed in both teſtaments, but little practiſed by many of Gods Whinnels, who are ever puling and putting ſinger in the eye, through one diſcontent or another. The wicked may not rejoyce. Hoſ. 9.1. the Saints muſt, Pſal. 32.11. and 33.1. and that continually, ſtriving to an habituall chearfulneſſe, which is when faith heals the conſcience, and grace huſheth the affections, and compoſeth all within; what ſhould ail ſuch a man, not to be perpetually merry?