Sirat alladhina an'amta alayhim ghayr al-maghdubi alayhim wa ad-dallin
The path of those whom You have favored, not those Your wrath is upon and not those who go astray
The following are excerpts of commentary on this ayah, based on Tafsir Ibn Kathir and other sources:
After the servant has requested for guidance to the Straight Path, Allaah then proceeds to clarify further what this Straight Path is.
Al-Ghadab linguistically means anger, it is the opposite of pleasure (ridaa) and one of the Attributes of Allaah. Maghdoob refer to the objects of Anger.
Dalaal linguistically means to divert from the intended goal or to diverge from the true path and it is the opposite of guidance. It is also said "the milk dalla in the water" when it is mixed such that it disappears.
At-Tirmidhee reports from Adee bin Haatim who said,
I asked the Messenger of Allaah (SAW) about Allaah's saying about, "those who have earned [Your] Anger", and He said, "it refers to the Jews." I then asked about, "those who have gone astray" and he said, "the Christians are those who have gone astray." [Reported by at-Tirmidhee and Ahmad and it is saheeh]
The Jews and the Christians even though both of them are misguided and both of them have Allaah's Anger on them - the Anger is specified to the Jews, even though the Christians share this with them, because the Jews knew the truth and rejected it and deliberately came with falsehood. Therefore the Anger of Allaah being upon them was the description most befitting them. The Christians were ignorant, not knowing the truth, so misguidance was the description most befitting them.
Ed. note: According to my understanding, the above refers to Jews and Christians who have learned the essentials of Islam and chosen to reject it, not to all Jews and Christians. People will not be called to account for what they are not aware of. And Allah SWT knows best
A Quranic Journal: Surah al-Fatiha ayah 7