A narration by Muslim has:

He said, "Call someone other than me as a witness to this." He then said, "Would you like them to be equal in their kind treatment of you?" He replied, "Yes." He said, "Don't do it, then."

وَفِي رِوَايَةٍ لِمُسْلِمٍ قَالَ : { فَأَشْهِدْ عَلَى هَذَا غَيْرِي" ثُمَّ قَالَ : " أَيَسُرُّكَ أَنْ يَكُونُوا لَكَ فِي اَلْبِرِّ سَوَاءً"? قَالَ : بَلَى .‏ قَالَ : " فَلَا إِذًا } [1]‏ .‏