David Cloud has an excellent article on his site that I encourage you to read. It deals with our tendency to speak of salvation using unbiblical phrases. We talk about "giving our life to Christ" or "inviting Jesus into our hearts" as if these phrases truly described the act of salvation. They do not. That does not mean that those who use these phrases are unsaved. It only means we are sloppy in our terminology. This is important because these phrases are also sloppy in doctrinal meaning. We are not saved by inviting Jesus into our hearts but by believing on Him. It is true that we receive Him (John 1:12But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
See All...; Colossians 2:6As ye have therefore received Christ Jesus the Lord, so walk ye in him:
See All...), but this refers more to a receiving of His way and person. Our hearts are deceitful and desperately wicked (Jeremiah 17:9The heart is deceitful above all things, and desperately wicked: who can know it?
See All...). Why should we invite Jesus in? The point is that we should get as close as possible to biblical terminology and meaning. Sloppy appeals for converts tend to make sloppy converts.

http://www.wayoflife.org/fbns/giving-my-life-to-jesus.html