An-Nisa 4:104

Wala tahinoo fee ibtigha-ialqawmi in takoonoo ta/lamoona fa-innahum ya/lamoona kamata/lamoona watarjoona mina Allahi ma layarjoona wakana Allahu AAaleeman hakeema

And do not weaken in pursuit of the enemy. If you should be suffering - so are they suffering as you are suffering, but you expect from Allāh that which they expect not. And Allāh is ever Knowing and Wise.

Do not show weakness in pursuing these people. If you are suffering, they are suffering as you are suffering, while you hope from Allah what they do not hope. Allah is All-Knowing, All-Wise.