English Standard Version (ESV)
God is faithful and true.
Mountains may crumble. The seas will fade away. Humans will be faithless, turning from God, choosing to worship other than the God who created and forgives us.
All of this will happen, and God will be faithful still.
Paul is correct in saying that our unrighteousness, our sin, presented the opportunity for God to display his amazing grace. But we are not to pursue sin as a way to show grace. We are wiser to choose gratitude for what God has done, for when faith grips our hearts we should race to God, choosing to worship and serve and share the Good News. This is the right response to the amazing gift we have been given, rather than to trod upon it in ingratitude, accepting the gift with no response.
May our lives show our gratefulness. May our hearts sing in joy. May we who have been blessed by the faithfulness of God seek to emulate God in all we do.