﴿ قَالَ لَنْ أُرْسِلَهُۥ مَعَكُمْ حَتَّىٰ تُؤْتُونِ مَوْثِقًۭا مِّنَ ٱللَّهِ لَتَأْتُنَّنِى بِهِۦٓ إِلَّآ أَن يُحَاطَ بِكُمْ ۖ فَلَمَّآ ءَاتَوْهُ مَوْثِقَهُمْ قَالَ ٱللَّهُ عَلَىٰ مَا نَقُولُ وَكِيلٌۭ ﴾

“Said [Jacob]: "I will not send him with you until you give me a solemn pledge, before God, that you will indeed bring him back unto me, unless you yourselves be encompassed [by death]!" And when they had given him their solemn pledge, [Jacob] said: "God is witness to all that we say!"”

He said ‘I will not send him with you until you give me a solemn pledge a covenant in the name of God by your swearing an oath that assuredly you will bring him back to me unless you are besieged’ such that you die or are overwhelmed and thus unable to bring him back. They agreed to this. And when they gave him their solemn pledge to this effect he said ‘God shall be Guardian Witness over what we say’ we and you. Thus he sent him with them.