Permissibility of rent

قَالُوا۟ يَٰذَا ٱلْقَرْنَيْنِ إِنَّ يَأْجُوجَ وَمَأْجُوجَ مُفْسِدُونَ فِى ٱلْأَرْضِ فَهَلْ نَجْعَلُ لَكَ خَرْجًا عَلَىٰٓ أَن تَجْعَلَ بَيْنَنَا وَبَيْنَهُمْ سَدًّۭا

They said: "O Zul-qarnain! the Gog and Magog (People) do great mischief on earth: shall we then render thee tribute in order that thou mightest erect a barrier between us and them?

قَالَ إِنِّىٓ أُرِيدُ أَنْ أُنكِحَكَ إِحْدَى ٱبْنَتَىَّ هَٰتَيْنِ عَلَىٰٓ أَن تَأْجُرَنِى ثَمَٰنِىَ حِجَجٍۢ ۖ فَإِنْ أَتْمَمْتَ عَشْرًۭا فَمِنْ عِندِكَ ۖ وَمَآ أُرِيدُ أَنْ أَشُقَّ عَلَيْكَ ۚ سَتَجِدُنِىٓ إِن شَآءَ ٱللَّهُ مِنَ ٱلصَّٰلِحِينَ

He said: "I intend to wed one of these my daughters to thee, on condition that thou serve me for eight years; but if thou complete ten years, it will be (grace) from thee. But I intend not to place thee under a difficulty: thou wilt find me, indeed, if Allah wills, one of the righteous."