Responsa for Bava Kamma 235:12

<big><strong>גמ׳</strong></big> אמר רב לדעת צריך דעת שלא לדעת מנין פוטר וכי קתני ומנו את הצאן והיא שלימה אסיפא

— No, we may still say that no demand was presented [on the part of the plaintiff], and the first clause is concerned with one who comes to fulfil his duty towards Heaven.<span class="x" onmousemove="('comment',' And since he is certain about the initial liability and only in doubt as to whether it was cancelled by payment, he is liable to make restoration for Heaven's sake even though there was no demand on the part of the plaintiff, whereas in the second clause where the doubt was regarding the initial liability it would not be so; cf. B.M. 37a and supra p. 600. ');">¹⁹</span> It was indeed so stated: R. Hiyya b. Abbah said that R. Johanan stated: If a man says to another, 'You have a <i>maneh</i> of mine,' and the other says, 'I am not certain about it,' he would be liable to pay<span class="x" onmousemove="('comment',' Provided there was a demand, for otherwise it would not be so since the initial liability is in doubt. ');">²⁰</span>

Teshuvot Maharam