Suppose I vote to admit Artur to our program because Artur is Polish. A colleague then criticizes me, not for my voting to admit Artur, who is indisputably an excellent candidate, but for my voting to admit Artur for the reason I did. The colleague says that I should have voted to admit Artur because of his qualifications, not his ethnicity. And of course the colleague would be right in the criticism.
It is a familiar phenomenon that when we make a decision, we can be morally criticized (by others or by ourselves) for acting on the reasons we did. Sometimes it is not up to us which reasons we act on—we might, after all, not be free at all, but be compelled to act on the reasons we act on. Such cases could lead to a paralysis: I know what I ought to do, and I know the reason I ought to do it for, but I am unable to do the action for the right reason.
I suspect that when we conscientiously realize that we are in a position where we are moved to do what we know is the correct action, but we know we are moved by reasons we should not be moved by, typically we are not helpless. We can in fact get ourselves to act for the right reasons. It would be too paradoxical if it were typical in such cases that the only way we had to avoid acting for the wrong reasons was to avoid the correct action.
But this means that we should be able to exercise some power of choice over the reasons for which we choose. To choose an action A for reason R is itself an action, and it is possible to have reasons for and against this action, since choice requires reasons. This threatens a regress of reasons.
One way to arrest the regress is to say that, in practice, our freedom eventually runs out. Eventually, we have no freedom to choose our reasons, but only freedom to choose the action. That may be the case sometimes. But I think a more interesting case would be where we can choose to act on a reason for that very reason, thereby arresting the regress. My love for my children, perhaps, not only provides me with reason to spend time with my children, but reason to do things out of love for my children.