The Prophet ﷺ said, "If a man promises his brother intending to fulfill it, but then fails to keep the promise and does not come at the appointed time, there is no sin upon him."
حدثنا محمد بن المثنى حدثنا أبو عامر حدثنا إبراهيم بن طهمان عن علي بن عبد الأعلى عن أبي النعمان عن أبي وقاص
عن النبي ﷺ قال إذا وعد الرجل أخاه ومن نيته أن يفي له فلم يف ولم يجئ للميعاد فلا إثم عليه
[Its chain of transmission is daif] Tirmidhi narrated it in the Book of Faith, chapter on what has been said regarding the sign of the hypocrite, hadith 2633, from the hadith of Abu Amir through this route, and he said, "Its chain is not strong." Abu Numan is unknown and Abu Waqqas is unknown.