Ray Yungen has put out various books, videos, Internet articles, etc. exposing the heresies of Spiritual Formation, with its New-Ageish core of contemplative prayer (also called contemplative spirituality).
Following is a two-part YouTube series of Yungen speaking on contemplative prayer/ contemplative spirituality:
And here is a YouTube video in which Yungen discusses “Contemplative/ Centering Prayer and Emergent Church.”
Click here for Ray Yungen’s website.