It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that a man pursued another man for his due (a debt) and pressed him insistently (in demanding it), so the Messenger of Allah (peace and blessings be upon him) said: "Whoever makes a demand (for his due), let him demand it with decency and restraint, whether he receives (his due) in full or not in full."
Hadith Referenceالمعجم الأوسط / باب الألف / 124
Hadith Takhrij«أخرجه ابن حبان فى «صحيحه» برقم: 5080، والحاكم فى «المستدرك» برقم: 2251، وابن ماجه فى «سننه» برقم: 2421، والبيهقي فى «السنن الكبرى» برقم: 11092، والبزار فى «مسنده» برقم: 5994»