What is the refutation against someone who claimed that the Messenger was in doubt about what was revealed to him, citing the verse: {But if you are in doubt as to what We have revealed to you, then ask…}?

The Prophet, peace and blessings be upon him, had no doubt about what was revealed to him, as evidenced by his statement when the verse was revealed: (And if you are in doubt about what We have revealed to you, then ask those who read the Scripture before you). He said: "I do not doubt, nor do I ask." The meaning of the verse is that it is an address to the Prophet by way of فرض ( فرض is a linguistic term that signifies a hypothetical or conditional premise, not a statement of fact or certainty), meaning: if you were in doubt, hypothetically, then ask. It was also said that the intended meaning is someone other than him, and it was also said that "doubt" here means constriction of the chest.