Reference for Eruvin 131:1
יפה עשיתם ששכרתם תהו בה נהרדעי ומי א"ר יוחנן הכי והא"ר יוחנן שוכר כמערב דמי מאי לאו מה מערב מבעוד יום אף שוכר מבעוד יום
You have acted well in renting the place'. The Nehardeans were astonished at this decision.<span class="x" onmousemove="('comment',' Just attributed to R. Johanan.');"><sup>1</sup></span> Could R'Johanan, [they argued,] have given such a decision, seeing that R'Johanan laid down that renting is subject to the same law as that of the preparation of an 'erub, which means, does it not, that as the preparation of an 'erub must take place while it is yet day so must renting also take place while it is yet day?<span class="x" onmousemove="('comment',' How then could it be asserted that R. Johanan approved of the renting of the heathen's share on the Sabbath?');"><sup>2</sup></span>