Yazid did not participate sincerely even in the later battles
History proves that even in the later battles, Yazid did not participate sincerely. Instead he participated only on the insistence of Hadhrat Ameer Mu'awiyah (May Allah be well pleased with him) as given in Tarikh Kamil Vol. 3, Pg No. 314, under the incidents of 49 and 50 Hijri:
Translation: Hadhrat Ameer Mu‘awiyah (May Allah be well pleased with him) sent a huge army to Rome in 50 Hijri. Hadhrat Sufyan bin ‘Auf (May Allah be well pleased with him) was appointed as the commander of the army and Yazid was ordered to go with the army. Yazid started making excuses, cited bad health and did not go. Hadhrat Ameer Mu‘awiyah (May Allah be well pleased with him) also did not go.
In this journey, the army faced hunger, thirst and a host of other difficulties. When Yazid was told about this, he recited some couplets, in which he said: I don't care about the fever, difficulties which the army faces at the Farqaduna (place name), at Dair Marwan, I am sitting on a high mattress and Umme Kulthoom (Yazid's wife) is with me.
When Hadhrat Ameer Mu‘awiyah came to know of this, he said with an oath, that Yazid should be definitely sent to the commander Hadhrat Sufyan bin ‘Auf (May Allah be well pleased with him), so that he understands the difficulties of the army. (‘Umdatul Qari Vol. 10, Kitab Ul Jihad; Al Tarikh Al Kamil, Dhikr Ghazwah Qustuntuniyah)
These details of ‘Umdatul Qari and Tarikh Al Kamil show the character of Yazid that to save himself from jihad, he made excuses. When the army faced difficulties, he expressed his happiness, which is in not allowed in the light of the Shariah. The Holy Prophet (Sallallahu alaihi wa sallam) has prohibited against expressing happiness on the difficulties of Muslims. There is a Hadith in Shu‘ab Ul Iman (Hadith No: 2507)
Translation: It is narrated on the authority of Hadhrat Waathila bin Asqa’a (May Allah be well pleased with him) that the Holy Prophet (Sallallahu alaihi wa sallam) said: You should not express happiness on the difficulty of your brother, lest Allah has mercy on him and embroil you in that difficulty.
Yazid did not obey his father's command which is a major sin. He feigned illness, even when he was healthy, which is lies and deception. Later, when Hadhrat Ameer Mu‘awiyah (May Allah be well pleased with him) put him under oath to go, he reluctantly joined the army. Can it be hoped that when he joined the army reluctantly, he would be rewarded for the Jihad, when the Holy Prophet (Sallallahu alaihi wa sallam) has said:
Translation: Verily, acts are rewarded according to the intentions. (Sahih Bukhari, Hadith No: 1, 54, 2549, 3897 5070, 6649, 6953)
Imam Badruddin ‘Aini (May Allah shower His mercy on him) says:
Translation: What excellence can be there for Yazid, when his state is so well known. (Umdatul Qari, Vol. 10, Pg No. 244)
Even if it is said that Yazid participated in Jihad with all his heart and is forgiven according to the Hadith, then does it mean that all his later sins are also forgiven? In the interpretation of the Hadith of the city of Caesar, the interpreters, Imam ‘Aini, Imam Ibn Hajar ‘Asqalani, Imam Qustullani (May Allah shower His mercy on them), all have written in the interpretation of this Hadith, that the forgiveness mentioned in this Hadith is only when the person is worthy of being forgiven.
It is written in ‘Umdatul Qari, Vol. 10, Pg No. 244:
Translation: Even if Yazid did join the army, even then because of his later crimes, he has been excluded from this glad tiding. For this reason, the scholars of the Ummah agree that the words, "they are forgiven" implies that if and only if they are worthy of being forgiven. If after participating in that battle, someone defects from Islam and then dies, then that person is not included in that glad tiding. This shows that the Hadith of the Prophet (Sallallahu alaihi wa sallam) means that the person joining in the army will be forgiven, only when the conditions of forgiveness are found in that person.