Some folk – especially Reformed people – are uneasy with the concept of “asking Jesus into your heart.” I can fully appreciate the way in which this phrase has been abused and butchered in various contexts. But I’m also concerned that Reformed-minded people are rejecting what, to me, is an obviously biblical truth. In fact, I think “asking Jesus into your heart” is not only relevant for non-Christians, but especially for Christians. After all, Christianity is a religion of the heart (Mark 12:30) and Christ is the sum and substance of our faith, hope, and love.
Free grace and faith have a special relationship to one another. Faith is the gift of God (Eph. 2:8). But that does not mean that God somehow believes for us. The “act” versus the “habit” distinction regarding faith safeguards God’s grace and human responsibility.
God grants the power to believe (the “habit”), but we perform the act of believing (the "act"). - @Mark_Jones_PCA
It is insufficient to merely possess the habit of faith in order to be justified; we must also produce an act of faith to be justified. True, the habit of faith enables us to believe, but we must really believe (i.e., it is our own act). Hence Paul speaks of the “obedience of faith” (Rom. 16:26), and as the Apostle John says, “But to all who did receive him, who believed in his name, he gave the right to become children of God” (John 1:12). If Christ isn't received into our hearts he is not received at all.
This distinction is not only relevant to a one-time event. It has relevance for the entire Christian life. When the habit is freely given to us from above, we receive the gift and then begin to put forth not just an act of faith, but acts of faith in God and Christ. We live by faith, daily.
Christ establishes a union with the elect sinner by “apprehending” him and then giving the Spirit to him. But this union is only complete (i.e., “ultimate union”) when the sinner exercises faith in Christ.
Pastorally speaking there are many advantages to the act-habit distinction in relation to union with Christ.
First, the faith that justifies is really our faith, which is why we are justified. The act of faith becomes the instrumental cause whereby we receive the righteousness of Christ and forgiveness of sins. Our act does not justify, but our act of faith is necessary for God to justify us.
Second, the faith that justifies is, however, enabled by the power (habitus) that God freely grants to us, apart from works. If God did not grant us the “habit” of faith, our “acts” of faith would be carnal and lifeless. There would be no true spirituality in our faith in God and Christ. Hence, we avoid the antinomian error whereby Christ believes for us. We also avoid a legalistic error because we contend that faith is not a result of the natural capacity of man.
Third, in relation to union with Christ, we hold that Christ, in his grace, first takes a hold of us and then enables us to take a hold of him in the act of believing. When this is done, and only when this is done, are we justified and “ultimate union” takes place. But we only unite ourselves to Christ because he first united himself to us. We love him because he first loved us.
Fourth, and finally, we must remember that our acts of faith towards Christ are lifelong acts. Faith is not a one-time event, but a “busy little thing.” Commenting on Ephesians 3:17 (“so that Christ may dwell in your hearts through faith”), Goodwin speaks of how our acts of faith relate to Christ dwelling in our hearts:
“For Christ to dwell in us by faith is that there may be a continual eyeing of Christ, and acting on Christ by us, as an object who has virtue to convey into us and to come in upon our hearts, and work upon our souls…for Christ to dwell in our hearts by faith is by operation and working, whereof faith is the instrument.”
Indeed, while some may be uncomfortable with the language of “receiving Jesus in to your heart,” we should remember that this (act-habit) distinction not only shows that “receiving Jesus” is biblical (see John 1:12), but also that “receiving Jesus” is something we do, through acts of faith, all our lives as Christians. Through faith “Christ said to dwell in the soul, by letting him into the soul and into the heart, and affecting the heart with him” (Goodwin).
Dispositions of love will arise in the heart when we put forth acts of faith in our Lord. If we are to ask for more of the Holy Spirit as Christians, how can we not ask for more of Christ? (see Luke 11:9-13).
In light of all of this, I would say that “asking Jesus into our heart” is the duty of Christians who wish to know more of the powerful indwelling of Christ who dwells in our hearts by faith. By asking for greater faith – as we should – we are asking for more of Christ because faith directly acts upon Christ’s person and work.
Yes, let us lament how "asking Jesus into your heart" has become, in some circles, almost a magic (and superstitious) formula. But, at the same time, let us not throw out what is a biblical concept when right understood, especially in relation to the Christian life.
In the Christian life you can possess something (or someone) and yet still need to ask for more. We grow in grace and faith - which is to grow in the powerful effects of Christ dwelling in our hearts by faith (Eph. 3:17). In fact, every time we take the Lord's Supper are we not asking Jesus into our heart afresh?
John Owen seemed to think so:
"As truly, my brethren, as we do eat of this bread, and drink of this cup, which is really communicated to us; so every true believer doth receive Christ, his body and blood, in all the benefits of it, that are really exhibited by God unto the soul in this ordinance: and it is a means of communicating to faith.
We come to receive a crucified Christ, come to be made partakers of the body and blood of the Lord,—to have the Lord Jesus really united to our hearts more and more. The Lord open our hearts to embrace the tender, receive the exhibition, take in Jesus Christ as food; that he may be incorporated in our hearts by faith, that he may dwell in us plentifully more and more,—that we may go away refreshed by this heavenly food, this glorious feast of fat things, which the Lord has made in his mount for his people! The whole of our comfort depends on our particular receiving of Christ by faith, and carrying him away by believing." (Works, 8:617-18).