What does it mean to be unregenerate? It means that you can relate to nothing but what your senses connect you with. It takes the ministry of the Holy Spirit to connect you with a greater world of reality that is in the promise of God. That is why the natural man doesn't receive the things that are of the Spirit of God. They are not spiritually discerned. You must have a spiritual discernment and the unregenerate person doesn't have that - he's sensual. Oh, he can relate to touch, taste, smell, all of these things - but he cannot connect with God.
Jim Gables (Faith vs Natural Senses)
What the unregenerate person desperately needs in order to come to faith is regeneration. This is the necessary grace. It is the sine qua non of salvation. Unless God changes the disposition of my sinful heart, I will never choose to cooperate with grace or embrace Christ in faith. These are the very things to which the flesh is indisposed. If God merely offers to change my heart, what will that accomplish for me as long as my heart remains opposed to him? If he offers me grace while I am a slave to sin and still in the flesh, what good is the offer? Saving grace does not offer liberation, it liberates. This is what makes grace so gracious: God unilaterally and monergistically does for us what we cannot do for ourselves
R.C. Sproul (Grace Unknown p. 188)