Al-Baqarah: 170
"And when it is said to them..."
"To them" (لهم):
The pronoun refers to "the people." The shift from the third person to the second person (addressing them directly) is a rhetorical device (iltifat) intended to highlight the extent of their misguidance. This is because there is no one more misguided than the blind imitator (muqallid). It is as if [God] is saying to the rational people: "Look at these fools and what they say."
It has been said that they are the polytheists, and it has been said that they are a group of the Jews whom the Messenger of God (peace be upon him) invited to Islam, to which they replied:
"Nay, we follow what we found our fathers upon." (Luqman: 21)
"Even if their fathers..." (أولو كان ءاباؤهم):
The waw (and) is for the state (hal), and the hamza (interrogative) denotes refutation and astonishment. The meaning is: "Will they follow them, even if their fathers did not understand anything of the religion and were not guided to the truth?"