Riyad as-Salihin 736
Jabir (May Allah be pleased with him) reported:
The Prophet (ﷺ) asked for sauce and was told that there was nothing except vinegar. He asked for it and began to eat from it saying, "How excellent is vinegar when eaten as sauce! How excellent is vinegar when eaten as Udm!" [Muslim] .
وعن جابر رضى الله عنه أن النبي صلى الله عليه وسلم سأل أهله الأدم فقالوا‏:‏ ما عندنا إلا خل، فدعا به، فجعل يأكل ويقول‏:‏ ‏
"‏نعم الأدم الخل، نعم الأدم الخل‏"‏ ‏.‏‏‏((رواه مسلم))‏