And fulfill the covenant of Allah when you have taken it, [O (16:91)

﴿وَأَوْفُوا بِعَهْدِ اللَّهِ إِذَا عَاهَدتُّمْ وَلَا تَنقُضُوا الْأَيْمَانَ بَعْدَ تَوْكِيدِهَا وَقَدْ جَعَلْتُمُ اللَّهَ عَلَيْكُمْ كَفِيلًا ۚ إِنَّ اللَّهَ يَعْلَمُ مَا تَفْعَلُونَ﴾
[ النحل: 91]

16:91 And fulfill the covenant of Allah when you have taken it, [O believers], and do not break oaths after their confirmation while you have made Allah, over you, a witness. Indeed, Allah knows what you do.

Fulfil every pledge that you made to Allah or that you made to people.
Do not break oaths after making them binding by swearing by Allah, when you have made Allah a witness to the oath that you swore.
Allah knows what you do.
Nothing is hidden from Him and He will recompense you for that.

And fulfill the Covenant of Allah (Bai'a: pledge for Islam) when you have covenanted, and break not the oaths after you have confirmed them, and indeed you have appointed Allah your surety. Verily! Allah knows what you do.

phonetic Transliteration

Waawfoo biAAahdi Allahi itha AAahadtum wala tanqudoo alaymana baAAda tawkeediha waqad jaAAaltumu Allaha AAalaykum kafeelan inna Allaha yaAAlamu ma tafAAaloona

Abdullah Yusuf Ali - Translation

Fulfil the Covenant of Allah when ye have entered into it, and break not your oaths after ye have confirmed them; indeed ye have made Allah your surety; for Allah knoweth all that ye do.

Safi-ur-Rahman al-Mubarakpuri

And fulfill the covenants (taken in the Name of) Allah when you have taken them, and do not break the oaths after you have confirmed them - and indeed you have appointed Allah as your guarantor. Verily, Allah knows what you do.

Page 277 English transliteration