It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that a woman made a vow to perform Hajj but she passed away. Her brother came to the Messenger of Allah (peace and blessings be upon him) and asked about this matter. The Messenger of Allah (peace and blessings be upon him) said: "If she had a debt, would you pay it off?" He replied, "Yes, I would certainly pay it off." He said: "Fulfill this vow, for fulfilling a vow is even more deserving."
Hadith Referenceسنن دارمي / من النذور و الايمان / 2369
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده صحيح والحديث متفق عليه، [مكتبه الشامله نمبر: 2377]
Hadith Takhrijاس روایت کی سند صحیح اور حدیث متفق علیہ ہے۔ دیکھئے: [بخاري 6699] ، [مسلم 1655]
Brief Explanation
(Commentary on Hadith 2368)
In the manuscripts of Sahih Bukhari and Sunan al-Darimi, it is stated: «فَاقْضِاللّٰهَفَاللّٰهُأَحَقُّبِالْقَضَاءِ ، أَوْفَهُوَأَحَقُّبِالْقَضَاءِ.» meaning, then fulfill the right of Allah as well, for He is most deserving that His right be fully fulfilled.