antique > ancient
2 Found no defect in its Creator's grace, 3 But with glad thanks, and unreproved truth,
unreproved > blameless; unreproving, uncomplaining truth > {Conduct in accordance with the divine standard; also a variant spelling of "troth", good faith}
4 The gifts of sovereign bounty did embrace: 5 Like angels' life was then men's happy case;
case > state
6 But later ages' pride, like corn-fed steed,
corn-fed > [pampered]
7 Abused her plenty, and fat swollen increase
her > [Nature's, referring to 207.15:4] fat swollen increase > [swollen with fat, increased]
8 To all licentious lust, and gan exceed