R. Yanai citing Rebbi: If the meaning of the wording of a document is unclear, one should read it to the detriment of the owner of the document.

R. Yochanan to R. Yanai: Isn't this an explicit Mishnah? As the Mishnah (daf 147 (b) above) teaches - R. Meir says - If the document did not specify that he was deathly ill but he said that he was deathly ill at the time etc. (He must prove that he was ill.)

R. Yinai would praise R. Yochanan for this response with the pasuk (Yishayahu 46: 6), "to those who pour out gold from the purse" and the pasuk (Mishlei 4, 21), "Don't let (my words) leave from your eyes etc."