Engagement in the church's practices puts us in a position where we may recognize and participate in the work of God's grace in the world.
[Practices] become arenas in which something is done to us, in us, and through us that we could not of ourselves do, that is beyond what we do.
The practices of Christian faith turn out in the end not primarily to be practices, efforts. They turn out to be places in the contours of our personal and communal lives where a habitation of the Spirit is able to occur. And it is this that is the source of their power and meaning. 
This is Craig Dykstra, in Growing in the Life of Faith: Education and Christian Practices, quoted by Glenn E. Sanders of Oklahoma Baptist University in 'How Christian Practices Help to Engage Students Morally and Spiritually: Testimony from a Western Civilization Course', his contribution to Teaching and Christian Practices: Reshaping Faith & Learning, edited by David I. Smith and James K.A. Smith.
It strikes me as a good, evangelical-friendly way to explain the effect of 'good works' that avoids the opprobrium that term acquires for those who are quick to smell 'works righteousness'. In fact, it also seems to apply well to the 'practice' of the Mysteries or Sacraments. This may be significant for evangelicals too, since I was baffled several years ago to hear one of them object to the idea that Baptism had any importance to salvation since it was a 'work' that we did rather than an act of God. In Dykstra's terms, the Mysteries may be something that we practice, but they are nevertheless 'done to us, in us, and through us', they are something 'we could not of ourselves do, that is beyond what we do'.
 Qtd. in Glenn E. Sanders, 'How Christian Practices Help to Engage Students Morally & Spiritually: Testimony from a Western Civilization Course', Teaching & Christian Practices: Reshaping Faith & Learning, ed. David I. Smith & James K.A. Smith (Grand Rapids, MI: Eerdmans, 2011), p. 161.