Jamieson, Fausset and Brown on Amos 5:16

16. Therefore--resumed from Am 5:13. God foresees they will not obey the exhortation (Am 5:14, 15), but will persevere in the unrighteousness stigmatized (Am 5:7, 10, 12).

the Lord--Jehovah.

the God of hosts, the Lord--an accumulation of titles, of which His lordship over all things is the climax, to mark that from His judgment there is no appeal.

streets ... highways--the broad open spaces and the narrow streets common in the East.

call the husbandman to mourning--The citizens shall call the inexperienced husbandmen to act the part usually performed by professional mourners, as there will not be enough of the latter for the universal mourning which prevails.

such as are skilful of lamentation--professional mourners hired to lead off the lamentations for the deceased; alluded to in Ec 12:5; generally women (Jr 9:17-19).