﴿ وَلَا تَتَّخِذُوٓا۟ أَيْمَٰنَكُمْ دَخَلًۢا بَيْنَكُمْ فَتَزِلَّ قَدَمٌۢ بَعْدَ ثُبُوتِهَا وَتَذُوقُوا۟ ٱلسُّوٓءَ بِمَا صَدَدتُّمْ عَن سَبِيلِ ٱللَّهِ ۖ وَلَكُمْ عَذَابٌ عَظِيمٌۭ ﴾

“And do not use your oaths as a means of deceiving one another-or else [your] foot will slip after having been firm, and then you will have to taste the evil [consequences] of your having turned away from the path of God, with tremendous suffering awaiting you [in the life to come].”

And do not make your oaths a means of deceit between you — He repeats this here for emphasis — lest a foot should slip that is lest your feet should slip off the path of Islam after being steady having been set upon it and lest you should taste evil that is chastisement forasmuch as you barred people from the way of God in other words for your refraining to fulfil covenants or barring others from doing this since your custom once established will be followed by others and there be a tremendous chastisement for you in the Hereafter.