Direct Operation of the Holy Spirit - The Holy Spirit accomplishes the new birth by direct operation upon the heart, and therefore works independently of all agency of man, including the gospel as preached by man.
Since the gospel is a spiritual thing, and since natural man rejects things of the Spirit, the gospel can never serve towards elevating natural men to a state of spirituality. Belief of the gospel is not a cause of spiritual birth; rather, it is a manifestation of such birth (Jn 1:11-13, Jn 5:24, Jn 8:43-47, Jn 10:25-27, Acts 13:48, 1Cor 1:18, Gal 5:22-23, 1Thes 1:4-5).
The scriptures teach that certain infants have experienced spiritual birth (Ps 8:2, Ps 22:9, Mt 11:25, Mt 21:16, Lk 1:15, Lk 1:41) even though infants are incapable of receiving the preached word. However, the scriptures offer no support to the theory that infants are spiritually quickened by means other than adults. Indeed, the opposite is suggested (Mk 10:15). Nor do the scriptures teach a different scheme of spiritual quickening for those in Old Testament times. There is but one method of spiritual quickening that can be common to all; namely, by direct operation of the Holy Spirit.
Jesus taught that those dead in trespasses and sins would be quickened by the power of his voice (Jn 5:25-29). In this same context it is taught this voice will also raise the bodily dead at the end of time. A man can give the words of Christ but not His voice, and as Christ will not use man to raise the bodily dead, neither does He use man to raise the spiritually dead.
If it were the purpose of the gospel to accomplish spiritual birth in natural men, then the gospel should be most urgently directed toward the nonspiritual. In fact, this is not its principal direction in the scriptures (2Thes 3:1-3, Rom 15:31, Acts 18:9-10).
Though certain of the elect may be deprived of the natural faculties or circumstances necessary to receive the preached word (2Sam 12:18-23, Mt 9:37-38, Rom 15:30-31, 2Thes 3:1), such considerations do not limit the power of God to directly reveal His Son in the hearts of all the elect (Mt 11:25, Mt 16:17, Mt 21:16, Lk 1:15, Lk 23:39-43, Jn 5:25, Jn 5:38, Jn 6:37, Jn 6:44-45, Gal 3:8, Heb 8:10-12).