He gave a horse called Ghumr or Ghumrah as a mount in the cause of Allah. Later he saw a colt or filly from its offspring being sold and attributed to his horse, so he forbade that.
حدثنا يحيى بن حكيم حدثنا يزيد بن هارون حدثنا سليمان التيمي عن أبي عثمان النهدي عن عبد الله بن عامر
أنه حمل على فرس يقال له غمر أو غمرة فرأى مهرا أو مهرة من أفلائها يباع ينسب إلى فرسه فنهى عنها
No references are available.
[Its chain of transmission is sahih] Ahmad narrated it: 1/164, from Yazid through the same chain, and Busiri said, This chain is sahih. Abdullah bin Amir is either Ibn Rabia or Ibn Kuraiz, and both are reliable narrators. Allah knows best.