[Jacob] said, "Never will I send him with you until you give (12:66)

﴿قَالَ لَنْ أُرْسِلَهُ مَعَكُمْ حَتَّىٰ تُؤْتُونِ مَوْثِقًا مِّنَ اللَّهِ لَتَأْتُنَّنِي بِهِ إِلَّا أَن يُحَاطَ بِكُمْ ۖ فَلَمَّا آتَوْهُ مَوْثِقَهُمْ قَالَ اللَّهُ عَلَىٰ مَا نَقُولُ وَكِيلٌ﴾
[ يوسف: 66]

12:66 [Jacob] said, "Never will I send him with you until you give me a promise by Allah that you will bring him [back] to me, unless you should be surrounded by enemies." And when they had given their promise, he said, "Allah, over what we say, is Witness."

Their father told them he would not send their brother with them until they had sworn by Allah that they would bring him back, unless destruction overwhelmed them all and none of them remained, and they were unable to do anything about it or to return.
When they had given their father a firm promise in Allah's name, he said that Allah was a witness over what they said, and His witnessing was sufficient for them.

He [Ya'qub (Jacob)] said: "I will not send him with you until you swear a solemn oath to me in Allah's Name, that you will bring him back to me unless you are yourselves surrounded (by enemies, etc.)," And when they had sworn their solemn oath, he said: "Allah is the Witness over what we have said."

phonetic Transliteration

Qala lan orsilahu maAAakum hatta tutooni mawthiqan mina Allahi latatunnanee bihi illa an yuhata bikum falamma atawhu mawthiqahum qala Allahu AAala ma naqoolu wakeelun

Abdullah Yusuf Ali - Translation

(Jacob) said: "Never will I send him with you until ye swear a solemn oath to me, in Allah's name, that ye will be sure to bring him back to me unless ye are yourselves hemmed in (and made powerless). And when they had sworn their solemn oath, he said: "Over all that we say, be Allah the witness and guardian!"

Safi-ur-Rahman al-Mubarakpuri

He [Ya`qub] said: "I will not send him with you until you swear a solemn oath to me in Allah's Name, that you will bring him back to me unless you are yourselves surrounded (by enemies)," And when they had sworn their solemn oath, he said: "Allah is the Witness to what we have said."

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