Ya`qub orders His Children to inquire about Yusuf and His Brother
Allah states that Ya`qub, peace be upon him, ordered his children to go back and inquire about the news of Yusuf and his brother Binyamin, in a good manner, not as spies. He encouraged them, delivered to them the good news and ordered them not to despair of Allah's mercy. He ordered them to never give up hope in Allah, nor to ever discontinue trusting in Him for what they seek to accomplish. He said to them that only the disbelieving people despair of Allah's mercy.
Yusuf's Brothers stand before Him
Allah said next,
فَلَمَّا دَخَلُواْ عَلَيْهِ
(Then, when they entered unto him), when they went back to Egypt and entered upon Yusuf,
قَالُواْ يأَيُّهَا الْعَزِيزُ مَسَّنَا وَأَهْلَنَا الضُّرُّ
(they said: "O Aziz! A hard time has hit us and our family..."), because of severe droughts and the scarcity of food,
وَجِئْنَا بِبِضَاعَةٍ مُّزْجَاةٍ
(and we have brought but poor capital,) means, `we brought money for the food we want to buy, but it is not substantial,' according to Mujahid, Al-Hasan and several others. Allah said that they said next,
فَأَوْفِ لَنَا الْكَيْلَ
(so pay us full measure) meaning, `in return for the little money we brought, give us the full measure that you gave us before.' Ibn Mas`ud read this Ayah in a way that means, "So give the full load on our animals and be charitable with us." Ibn Jurayj commented, "So be charitable to us by returning our brother to us." And when Sufyan bin `Uyaynah was asked if the Sadaqah (charity) was prohibited for any Prophet before our Prophet , he said, "Have you not heard the Ayah,
فَأَوْفِ لَنَا الْكَيْلَ وَتَصَدَّقْ عَلَيْنَآ إِنَّ اللَّهَ يَجْزِى الْمُتَصَدِّقِينَ
(so pay us full measure and be charitable to us. Truly, Allah does reward the charitable.)" Ibn Jarir At-Tabari collected this statement.
Tafsir Ibn Kathir (abridged, English).