It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that Sayyiduna Hibban bin Munqidh (may Allah be pleased with him) had some deficiency in understanding due to a head injury, and this injury also caused a stutter in his speech. He used to be deceived in transactions, so the Messenger of Allah (peace and blessings be upon him) fixed a three-day option for him in his purchases, and the Messenger of Allah (peace and blessings be upon him) said to him: "When making a transaction, say: 'There will be no deception.'" Sayyiduna Ibn Umar (may Allah be pleased with him) says that I heard him (while transacting) saying «لا خلابة لا خلابة». "There will be no deception, there will be no deception."
Hadith Referenceالسنن المأثورة / باب في البيوع / 260
Hadith Takhrijمسند الحمیدی : 292/2، رقم : 662، سنن دار قطنی : 55,54/3، السنن الكبرى للبيهقي : 273/5، مسند احمد : 282/10، رقم : 6134 وقال الارنوؤط: حديث صحيح وهذا اسناده حسن، وصححه ابن الجارود، رقم : 567