Ishaq—who is Ibn Ibrahim ibn al-Ala ibn Zubayriq al-Himsi—I have not identified. Al-Tabarani transmitted from him one hadith in al-Mu'jam al-Saghir (542—al-Rawd), and four other hadiths in al-Awsat (2/304/2–305/1/5039–5042). He narrated extensively from him in Musnad al-Shamiyyin, both before this hadith and afterwards, up to p. 331 (1). In all of them, Muhammad ibn Isma'il explicitly states that he narrated directly from his father; he does likewise on pp. 334 and 335. Hashim ibn Marthad al-Tabarani also corroborated him in reporting direct narration from his father, in the same work (pp. 331 and 334). Perhaps he was one of al-Tabarani’s trustworthy shaykhs, which may be why al-Dhahabi did not include him in al-Mizan. And Allah knows best.
Among the reports that strengthen the hadith is what al-Bukhari, Muslim, and others narrated from Sa'd ibn Abi Waqqas: the Messenger of Allah, peace and blessings be upon him, said: “You will not spend anything seeking thereby the pleasure of Allah except that you will be rewarded for it, even the morsel you put in your wife’s mouth.” al-Irwa' (899).
2737 — “Whoever sees an afflicted person and says: ‘Praise be to Allah, who has spared me from what He has afflicted you with and favored me greatly over many of those He has created,’ will not be afflicted by that calamity.”
Al-Tabarani narrated it in al-Mu'jam al-Awsat (2/25/1/5457): Muhammad ibn Ahmad ibn Abi Khaythamah narrated to us; he said: Zakariyya ibn Yahya al-Darir informed us; he said: Shababah ibn Sawwar informed us. Al-Mughirah ibn Muslim said: from Ayyub, from Nafi', from Ibn Umar, who said: The Messenger of Allah, peace and blessings be upon him, said it. And he said: