The issue is that there is no combining of Jumu'ah and 'Asr.

The Shaykh : I would also like to speak about an issue that may occur for some people who travel after the Friday prayer. Some people, when they pray Jumu'ah and intend to travel, combine 'Asr with it, thinking that combining 'Asr with Jumu'ah is permissible. They think that combining 'Asr with Jumu'ah is allowed, but that is not the case. Combining 'Asr with Jumu'ah is not permissible. Whoever combines 'Asr with Jumu'ah has prayed it before its time, and it is not permissible to advance a prayer before its time except with a Shari'ah proof. It has not been reported from the Prophet (peace and blessings be upon him) that he combined 'Asr with Jumu'ah. Acts of worship are based on what? On restriction and evidence. If it has not been reported from the Prophet (peace and blessings be upon him), in a weak or authentic hadith, that he combined 'Asr with Jumu'ah, then we have no right to combine 'Asr with Jumu'ah, because if we did so, we would be praying 'Asr before its time, and a prayer before its time is invalid.
If someone were to say: "I will analogize Jumu'ah to Zuhr and say that 'Asr is combined with Jumu'ah just as it is combined with Zuhr, based on the hadith of 'Abdullah ibn 'Abbas (may Allah be pleased with him) who said: — Watch out, my brother... you are looking around to the right and left, you are losing something, you — based on the hadith of Ibn 'Abbas (may Allah be pleased with them both) who said: meaning that it does not cause hardship for them in not combining, and he says: "If the Messenger combined 'Asr with Zuhr, then let us combine 'Asr with Jumu'ah." We say: This analogy is incorrect, because Jumu'ah differs from the 'Asr prayer in more than thirty rulings. If it differs from it in more than thirty rulings, how can it be attached to it? If we want to make an analogy, it is attaching a branch to a root in a ruling for what? For a common cause. And there must be equality between the thing being analogized and the thing it is analogized to. Is congregation a condition for Jumu'ah or not? Answer, everyone. Yes. Is time a condition for Jumu'ah or not? And is congregation a condition for Zuhr? It is not valid for the one who prays alone. Is time a condition for it? No, time is not a condition for it, everyone. If I make a mistake, correct me, may Allah reward you with good. Jumu'ah has time as a condition, while Zuhr does not have time as a condition. Is that wrong or correct? No, it is correct, except that Jumu'ah has the entry of the time as a condition. If a person sleeps or forgets it, he prays it whenever? After the time. If he sleeps and does not wake up until after the time, he prays after the time. But Jumu'ah, if its time passes, he does not pray it as Jumu'ah; he prays it as Zuhr. So Jumu'ah has time as a condition, and Zuhr does not have time as a condition. But Zuhr has what as a condition? The entry of the time. And the difference between the two expressions is clear. Jumu'ah is not valid except in villages and cities, and it is not valid while traveling. If a group of travelers wanted to combine, it would not be valid, even if they gave the sermon and prayed, it would not be valid. Is Zuhr valid while traveling or not valid? It is valid. Good. Jumu'ah is two rak'ahs in the city, and it is not established while traveling. How many rak'ahs is Zuhr in the city? Four rak'ahs. Jumu'ah is read with loud recitation, and Zuhr is read quietly. Jumu'ah is not established in more than one place in the town except for a need, while Zuhr is established in every mosque in the neighborhood. And the differences are more than thirty differences. And if that is the case, the analogy is not valid. We now have a Shari'ah textual proof, which is that acts of worship are based on what? On restriction, meaning on what has come from the Shari'ah. And it has not come from the Shari'ah to combine 'Asr with Jumu'ah. Second, there is no analogy between Zuhr and Jumu'ah due to the existence of many differences. And I tell you, does not a Jumu'ah with rain pass by the Prophet (peace and blessings be upon him)? Answer, yes, it passes by. The man who entered on the day of Jumu'ah and said: "O Messenger of Allah, ask Allah to send us rain." The sky rained until the second Jumu'ah, and the Messenger did not combine 'Asr with it, even though he combines Zuhr and 'Asr in the rain. In any case, I wanted to point this out because the question about it is frequent, and the difficulty regarding it is also great for some people. But praise be to Allah, if a person clarifies the evidence and reflects on it, he finds that whoever combines 'Asr with Jumu'ah has prayed 'Asr before its time without permission from the Shari'ah, and he must repeat it if he has done so.