How can one identify the hadith referred to by Imam Al-Nawawi in the Forty Hadith, given a slight difference in the text and chain of transmission between the narrations found in Al-Bukhari and Muslim?

The hadith, "Indeed, actions are by intentions," is a single hadith that Al-Bukhari and Muslim agreed upon narrating. Its chain of narration revolves around one source, as its various chains trace back to Yahya ibn Sa'id al-Ansari, from Muhammad ibn Ibrahim al-Taymi, from Alqama ibn Waqqas al-Laythi, from Umar ibn al-Khattab, may Allah be pleased with him. The hadith became widely transmitted from Yahya ibn Sa'id al-Ansari, and many of his students narrated it from him. As for the slight variations in some of its wordings, they do not preclude it from being a single hadith, because narrating a hadith by its meaning is permissible according to scholars, as long as the meaning does not change. This is what Imam Muslim did by quoting the hadith and then indicating that all other narrations from Yahya ibn Sa'id convey the same meaning.