It was customary for the Jews to dance when they were very happy. The abstract nouns "mourning" and "dancing" can be stated as verbs. Alternate translation: "You have caused me to stop mourning and to dance with joy instead" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
Sackcloth was associated with mourning and sorrow. Alternate translation: "You have caused me to no longer be sad" (See: [[rc://en/ta/man/translate/figs-metonymy]])
The writer speaks of gladness as if it were a garment that he could put on. Alternate translation: "caused me to be glad" (See: [[rc://en/ta/man/translate/figs-metaphor]])