in summary: the narrators differed regarding Ibn Abī Fudayk in the isnād of this ḥadīth, and most of them said: from him, from al-Ḍaḥḥāk ibn ʿUthmān, from Muḥammad ibn al-Munkadir, from ʿAbd al-Raḥmān ibn Yarbūʿ, from Abū Bakr. This isnād consists of trustworthy men according to Muslim, but it is disconnected because Ibn al-Munkadir did not hear from Ibn Yarbūʿ, as mentioned earlier in al-Tirmidhī's statement, and Allāh knows best. Then I found a supporting narration for it. Abū Yaʿlá said in his "Musnad" (3/1260-1261): Abū Hishām al-Rifāʿī narrated to us, Abū Usāmah informed us, Abū Ḥanīfah informed us, from Qays ibn Muslim, from Ṭāriq ibn Shihāb, from ʿAbd Allāh who said: The Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam) said: and he mentioned it and added, "As for the 'ʿaj', it is the talbiyah, and as for the 'thaj', it is the slaughtering of the sacrificial animals." This isnād consists of trustworthy men according to Muslim, with a weakness in al-Rifāʿī, whose name is Muḥammad ibn Yazīd ibn Muḥammad, other than Abū Ḥanīfah, who is weakened by the majority of the ḥadīth scholars, but he is not accused, so the ḥadīth is considered ḥasan. And Allāh knows best