The proponents of this view cite as evidence that one night in Ramadan, the Prophet ﷺ stood praying, and some people gathered around him and prayed with him, though he had not been aware of them. He then prayed on the second and third nights and became aware of them, but on the fourth night he held back out of fear that it might be made obligatory upon them.⦗1⦘ This is the view of Imam Malik,⦗2⦘ and it is the sounder opinion.
This is because what is sought is that the follower keep in step with the imam, and that has been achieved. In this case, the follower receives the reward of congregational prayer, whereas the imam does not, because the follower made the intention and thus receives what he intended, while the imam did not make the intention and therefore does not receive what he did not intend.
The fifth case: the imam makes the intention, but the follower does not. For example, a man comes and stands beside another man and says the opening takbir. The first man assumes that he wishes to follow him, so he intends to lead the prayer; yet this man did not intend to follow him. In this case, neither the imam nor the follower receives the reward of congregational prayer, because there is no congregation: the follower neither followed the imam nor took him as his example, while the imam intended to lead but had no one to lead. Thus, the reward of congregational prayer is not attained when there is no congregation.
If someone were to say that the imam receives the reward in this case, that would not be far-fetched, in view of the general import of the Prophet’s ﷺ statement: “Actions are only by intentions, and every person shall have only what he intended.”⦗3⦘