The verb “to avenge” means to intentionally cause harm as retribution for wrongdoing. In this context, gunnery practice is portrayed as posturing a nation’s “readiness” to violently return the harm inflicted by its enemies.
The adverb “sorely” means to a high or extreme intensity. God hints that, when he “‘blow[s] the trumpet,’” the warmongers will be sent “‘to scour/ Hell’s floor’” as punishment for their warfare. Therefore, they sorely—or greatly—need “‘the judgment-hour’” to be postponed in favor of “‘rest[ing] eternal.’”
The word “glebe” refers to a plot of cultivated land used to generate revenue for a church or parish. Therefore, a “glebe cow” is a cow kept on this land for the purpose of making money for the church.
A “chancel” is an area of a church, often near the altar at the eastern side of the building. The chancel is usually reserved for the church’s choir or the clergy.
