Contradiction with Jeremiah 48:47
While Isaiah 23:12 speaks of not rejoicing, Jeremiah 48:47 hints at a future restoration and joy for Moab.
Jeremiah 48:47: Yet will I bring again the captivity of Moab in the latter days, saith the LORD. Thus far [is] the judgment of Moab.
Contradiction with Isaiah 43:19
Isaiah 23:12 talks about restraint, while Isaiah 43:19 emphasizes new beginnings and making a way.
Isaiah 43:19: Behold, I will do a new thing; now it shall spring forth; shall ye not know it? I will even make a way in the wilderness, [and] rivers in the desert.
Contradiction with Matthew 5:4
Isaiah 23:12 discourages rejoicing, unlike Matthew 5:4 which speaks of those who mourn being blessed and comforted.
Matthew 5:4: Blessed [are] they that mourn: for they shall be comforted.
Contradiction with Isaiah 61:3
Contrasts Isaiah 23:12’s call for abstaining from celebration with promises of joy replacing mourning in Isaiah 61:3.
Isaiah 61:3: To appoint unto them that mourn in Zion, to give unto them beauty for ashes, the oil of joy for mourning, the garment of praise for the spirit of heaviness; that they might be called trees of righteousness, the planting of the LORD, that he might be glorified.
Contradiction with Proverbs 17:22
Talks about a merry heart being beneficial, in contrast to Isaiah 23:12's admonishment against rejoicing.
Proverbs 17:22: A merry heart doeth good [like] a medicine: but a broken spirit drieth the bones. [like: or, to]