﴿ يُرِيدُ ٱللَّهُ أَن يُخَفِّفَ عَنكُمْ ۚ وَخُلِقَ ٱلْإِنسَٰنُ ضَعِيفًۭا ﴾

“God wants to lighten your burdens: for man has been created weak.”

(Allah would make the burden light for you) He wishes to make things easy for you by marrying captives in case of necessity, (for man was created weak) in that he cannot do without women.