The new wine languisheth - The new wine (תירושׁ tı̂yrôsh), denotes properly must, or wine that was newly expressed from the grape, and that was not fermented, usually translated ‘new wine,’ or ‘sweet wine.’ The expression here is poetic. The wine languishes or mourns because there are none to drink it; it is represented as grieved because it does not perform its usual office of exhilarating the heart, and the figure is thus an image of the desolation of the land.
The vine languisheth - It is sickly and unfruitful, because there are none to cultivate it as formerly. The idea is, that all nature sympathizes in the general calamity.
All the merry-hearted - Probably the reference is mainly to those who were once made happy at the plenteous feast, and at the splendid entertainments where wine abounded. They look now upon the widespread desolation of the land, and mourn.