3:166 wa maa aSaabakum yawmaltaqal jam'AAni fa bi idhnil-laahi wa li ya'Ålamal mu'miniyn

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Ahmed Raza Khan: Mohammed Aqib Qadri:
And the calamity that struck you on the day the two armies met, was by Allah's command - and in order that He may make known the believers.

Yusuf Ali:
What ye suffered on the day the two armies Met, was with the leave of Allah, in order that He might test the believers,-

Pickthal:
That which befell you, on the day when the two armies met, was by permission of Allah; that He might know the true believers;