What is the meaning of "man" (whoever/all those who are) and "kulluhum jamee'an" (all of them entirely/all of them collectively) in the verse: (And if your Lord had willed, all those on earth would have believed, all of them entirely. So, would you then compel the people until they become believers)?

The Holy Qur’an states that if Allah Almighty had willed, all the people on Earth would have believed. It also states that the Prophet, peace and blessings be upon him, was not tasked with compelling people to believe, but only with conveying the message. Humans have free will and choice to believe or disbelieve, and they are recompensed for their deeds because Allah Almighty wrongs no one. Allah knows what the destiny of every servant will be and has recorded it with Him. He misguides whom He wills and guides whom He wills by His wisdom and knowledge. Humans are given a choice and are recompensed for their choice. Allah knows what the servant’s destiny will be, and He extends His aid to the believers and abandons whom He wills, out of His justice. The servant must seek Allah's help, acknowledge His grace and blessings upon him, and strive for what benefits him in the Hereafter. Allah's will pertains to His action and the servant's action; He wills to aid and grant success to the servant, and the servant's action is not completed except by Allah's will and His aid to him.