لاdo not تُفسِدَنspoil (emphatic) سابِقَprevious إِحسانٍan act of kindness مَضىhas passed
لا تُفسِدَن سابِقَ إِحسانٍ مَضى
وَاللَهُand God لاnot يُغلَبُbe overcome فيماin what قَدalready مَضىhas passed
وَاللَهُ لا يُغلَبُ فيما قَد مَضى
Do not spoil a past act of kindness.
Do not spoil the good you did in days gone by,
Do not corrupt the former kindness that has passed,
And God cannot be overcome in what has already passed.
For God's will in the past cannot now be undone.
And God is not defeated in what has gone before.