Do not upset yourself, whatever form of life or devotion God may give to anyone. If I were so good and holy that they were to raise me to the altars with the saints, still people would be talking and worrying about whether this were grace or nature working in me, and puzzling themselves about it. They are all wrong in this. Leave God to work in you, let him do it, and do not be upset over whether he is working with nature or above nature; for nature and grace are both his. What has that to do with you, what it suits him to work with, or what he may work in you or in someone else? He must work how or where or in what way is fitting for him.
There was a man who would dearly have liked to make a stream flow through his garden, and he said, "If the water could be mine, I should not care what sort of channel brought it to me, iron or timber, bone or rusty metal, if only I could have the water." And so anyone is quite wrong who worries about the means through which God is working his works in you, whether it be nature or grace. Just let him work, and just be at peace.
(From the "Counsels on Discernment" in Meister Eckhart: The Essential Sermons, Commentaries, Treatises, and Defense, eds. Edmund Colledge, OSA and Bernard McGinn (Paulist, 1981), 284-5)