Umar bin Hamza bin 'Abdullah عمر بن حمزة بن عبد الله بن عمر · Commercial Transactions (Kitab Al-Buyu)

The Messenger of Allah (ﷺ) sent with him a dinar to buy a sacrificial animal for him. He bought a sheep for a dinar, sold it for two and then returned and bought a sacrificial animal for a dinar for him and brought the (extra) dinar to the Prophet (ﷺ). The Prophet (ﷺ) gave it as alms (sadaqah) and invoked blessing on him in his trading.