Surah Al-Nahl (The Bees), Verse 94

وَلَا تَتَّخِذُوْۤا اَیْمَانَكُمْ دَخَلًا بَیْنَكُمْ فَتَزِلَّ قَدَمٌ بَعْدَ ثُبُوْتِهَا وَتَذُوْقُوا السُّوْٓءَ بِمَا صَدَدْتُّمْ عَنْ سَبِیْلِ اللّٰهِ وَلَكُمْ عَذَابٌ عَظِیْمٌ ۟

Wa laa tattakhizooo aimaanakum dakhalam bainakum fatazilla qadamum ba'da subootihaa wa tazooqus sooo'a bima sadattum 'an sabeelil laahi wa lakum 'azaabun 'azeem

“And take not your oaths, to practise deception between yourselves, with the result that someone's foot may slip after it was firmly planted, and ye may have to taste the evil (consequences) of having hindered (men) from the Path of Allah, and a Mighty Wrath descend on you.”

Quran 16:94 (Yusuf Ali Translation)