‘And while Peter thought on the vision, the Spirit said to him, “Behold, three men are looking for you. But arise, and get you down, and go with them, nothing doubting, for I have sent them.”
Peter's mind was still on the vision and the Spirit then told him about the two servants and the soldier who were looking for him, and told him that he must go down to them, and go with them without having any doubts, because it was God Himself Who had sent them. As he probably had a conscience about having resisted God already, this more reasonable request would make it an easier command to obey. But God was not just wanting Peter to be willing to approach Gentiles. He wanted him to see that Gentiles on whom He laid His hands were thereby totally clean and wholesome and to be thoroughly welcomed. He was breaking down great prejudice. And because this was Peter, a representative of the Apostles, not only for Peter but also for the Apostles as a whole.
‘The Spirit told him.' The Spirit could speak directly to Peter for he was a man of the Spirit.
‘Three men.' B has ‘two men'. Aleph, A, E have ‘three men'. Some MS (e.g. D) do not mention a number. B may well be right. But in view of the description of those sent either number is possible. The soldier was an escort and not strictly one of the seeking men. Thus two men (deputed servants) were seeking Peter, along with an escort. On the other hand the three would go well as a parallel with the threefold vision. Three ‘clean' men.
‘Nothing doubting.' Peter is to go with them confidently and without making unnecessary difficulties, or allowing his sense of what was ‘unclean' to affect his decision, for what is to happen has been cleansed by God. In the middle or passive voice this verb can mean either "to take issue with" or "to be at odds with oneself, to doubt, to waver, to have misgivings". As an intensified form of its active meaning it could mean "to make a distinction, to differentiate". Possibly both ideas are in mind. Religiously speaking he need not analyse the situation because God is in it. He can forget his worries and he need not consider distinctions, for when God has determined something it can no longer be treated in the ordinary way.