What is the interpretation of the verse: (The truth is from your Lord, so do not be among the doubters) [Aal ‘Imran/60], and what is the easiest way to respond to someone who claims that the verse indicates Prophet Muhammad’s doubt (peace be upon him) regarding the Quran?

Allah's prohibition to His Prophet, peace and blessings be upon him, against doubt, by His saying: "The truth is from your Lord, so be not among the doubters," does not mean that the Prophet experienced doubt. Rather, it was to strengthen his heart and incite him to steadfastness, and as a warning to the believers so that they would not doubt. An example of this is His, the Almighty's, saying: "And if you are in doubt about what We have revealed to you, then ask those who have been reading the Scripture before you." For the suspension of a ruling upon a condition does not necessitate the occurrence of the condition. And the Prophet, peace and blessings be upon him, never doubted what was revealed to him, for he was the greatest of people in faith and certainty. And it may be that the address is to him, but what is intended are others among the believers.