The Prophet (peace and blessings be upon him) said:
"Presenting witnesses and proof is the responsibility of the claimant (the one making the claim), and taking the oath is the responsibility of the defendant (the one against whom the claim is made)."
Hadith Referenceصحیح الجامع الصغیر / حرف الباء / 2897
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[ت] عن ابن عمرو. الإرواء ٢٦٤١، ٢٦٦١، ٢٦٨٥.