was broken, because Ḥabīb ibn Thābit never heard directly from Ḥakīm and the chain also contains an unnamed narrator.
I say: this only concerns the corroborating report and does not undermine the primary hadith itself.

Takeaways from the hadith:

1. Agency is permissible in matters that accept delegation, such as buying and selling; the Prophet ﷺ appointed ʿUrwah al-Bāriqī to purchase the sheep on his behalf.
2. The hadith shows that a transaction concluded by an unauthorized person (al-fuḍūlī) becomes valid once it is ratified by the one for whom he acted, and the transaction is then attributed to that person. This is one narration in the Hanbalī school. Shaykh ʿAbd al-Raḥmān al-Saʿdī said: The correct view is that the fuḍūlī’s sale or purchase is sound if the principal approves it. The well-known position in the school, however, is that the fuḍūlī’s act remains invalid even after approval, yet the other narration is stronger, Allah willing, and the hadith of ʿUrwah al-Bāriqī is explicit on its permissibility.
3. Purchasing the sheep in this report did not irrevocably designate it as the sacrificial animal, so it could still be exchanged. A purchase may serve many aims; designation occurs only when one says, “This is a sacrifice,” or, “This is for Allah.” Had designation occurred merely by purchase, it would have been impermissible to sell or gift it, since Allah’s right would then attach to it.
4. The Prophet’s supplication bestowed such blessing on the man that he never lost on a deal; even had he bought mere dust, he would have profited from it.
5. Supplication is an appropriate recompense for someone who renders a favor, brings benefit, or gives a gift.
6. Rejoicing over worldly gain does not conflict with turning toward Allah as long as the world is not the person’s chief concern; he is pleased with it only to meet his obligations and expenses, without seeking to accumulate or flaunt it.