Ask the average Christian how they were saved and most will include, at some point in their story, that “I asked Jesus into my heart.” I’ve said it before, too. I think it’s okay to say with the right theological framework; however it is a very loaded phrase.
I am currently reading Graeme Goldsworthy’s Gospel-Centered Hermeneutics, and he talks about how this notion of salvation obscures the true biblical gospel. He calls “Jesus-in-my-heart-ism” ‘evangelical Catholicism’. He explains:
Many evangelicals use the evangelistic appeal to ‘ask Jesus into your heart.’ The positive aspect of this is that the New Testament speaks of ‘Christ in you, the hope of glory’ (Col. 1:27); of Christ dwelling ‘in your hearts through faith’ (Eph. 3:17), and the like. It speaks of the Christian as having ‘received Christ the Lord’ (Col. 2:6). But it also makes clear that Christ dwells in or among his people by his Spirit, for the bodily risen Jesus is in heaven. Furthermore, there are no examples or principles of evangelism or conversion in the New Testament involving the asking of Jesus into one’s heart. In many cases this practice represents a loss of confidence in faith alone, for it needs to resort to a Catholic style of infused grace to assure us that something has happened.
Now, when people are genuinely converted by asking Jesus into their hearts, and I have no doubt that there are many, it can only be because they have understood the gospel sufficiently well for this prayer to be a decision to believe that this Jesus is the one who lived and died for their salvation. Why, then, have I called this section ‘evangelical Catholicism’? An aspect of Catholicism that Protestants have rejected is the reversal of the relationship of objective justification to is subjective outworking or sanctification. Another way of putting this is that the focus on the grace of God at work in the historic gospel even of Jesus Christ is muted compared to the emphasis on the grace of God as a kind of spiritual infusion into the life of the Christian. The gospel is see more as what God is doing in me now, rather than what God did for me then…When the legitimate subjective dimension of our salvation begins to eclipse the historically and spirituality prior objective dimension, we are in trouble.
– Graeme Goldsworthy, Gospel-Centered Hermeneutics, p. 176.