“Our sense of free will results from a failure to appreciate this: We do not know what we intend to do until the intention itself arises. To understand this is to realize that we are not the authors of our thoughts and actions in the way that people generally suppose.”

Source: The Divine Conspiracy: Rediscovering Our Hidden Life In God

As rendered by T. Byrom (1993), Shambhala Publications.
There is no quote from the Pali Canon that matches up with any of these. The closest quote to this is in the Majjhima Nikaya 19:
"Whatever a monk keeps pursuing with his thinking & pondering, that becomes the inclination of his awareness. If a monk keeps pursuing thinking imbued with sensuality, abandoning thinking imbued with renunciation, his mind is bent by that thinking imbued with sensuality. If a monk keeps pursuing thinking imbued with ill will, abandoning thinking imbued with non-ill will, his mind is bent by that thinking imbued with ill will. If a monk keeps pursuing thinking imbued with harmfulness, abandoning thinking imbued with harmlessness, his mind is bent by that thinking imbued with harmfulness." Sources: http://www.accesstoinsight.org/tipitaka/mn/mn.019.than.html
Misattributed

Source: The Way of All Flesh (1903), Ch. 5

Source: Where Angels Fear to Tread

Source: A Beginner's Guide to the Path of Ascension (The Ascension Series)

Source: Lullaby

Spoken on his return to India from England as recorded in From Colombo to Almora (1904), Calcutta, p. 221
Context: No one ever landed on English soil with more hatred in his heart for a race than I did for the English, and, on this platform, are present English friends who can bear witness to the fact, but the more I lived among them, saw how the machine is working, the English national life, mixed with them, found where the heart-beat of the nation was, the more I loved them. There is none among you here present, my brothers, who loves the English people more than I do. You have to see what is going on there, and you have to mix with them. As the philosophy, our national philosophy of the Vedanta, has summarised all misfortune, all misery from that one cause, ignorance, herein also we must understand that the difficulties that arise between us and the English people are mostly due to that ignorance; we do not know them, they do not know us.