In any case, he should eat dates—at least three—before going out for the Eid al-Fitr prayer.
His statement, “The reverse applies to al-Adha if he offers a sacrifice,” means the reverse of eating, namely, refraining from eating on Eid al-Adha. Thus, he should not eat before the Eid al-Adha prayer, so that he may eat from his sacrifice, as stated in the hadith of Buraydah: “The Prophet, peace and blessings be upon him, would not go out on the day of al-Fitr until he had broken his fast, and he would not eat on the Day of Sacrifice until he had prayed.” Recorded by Ahmad (1).
This is also because it hastens his eating from his sacrificial animal. Eating from the sacrifice is considered obligatory by some scholars, based on Allah’s saying:
“Eat from them and feed others.” [al-Hajj 22:28, 36]
He began with the command to eat. It is therefore preferable to refrain from eating on Eid al-Adha until one eats from the sacrifice from which one has been commanded to eat.
As for the wisdom behind eating early on Eid al-Fitr, it is to establish breaking the fast at the beginning of the day. The preceding day was one on which fasting was obligatory, whereas this day is one on which breaking the fast is obligatory; thus, hastening to establish this is better. Accordingly, if he eats these dates before praying Fajr, the intended purpose is fulfilled, since he ate them during the daytime. However, it is preferable to do so when he intends to go out.
His statement, “if he offers a sacrifice,” implies that if he does not have a sacrifice, then it is not prescribed for him to refrain from eating before the prayer; rather, he has the choice.