"It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto, they are spirit, and they are life." John 6:63 "And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father." John 6:65 I would refer back to these verses in the previous chapter of John and then move on to John 7. John Gill writes some on this occasion, especially setting it into its historical perspective. The Jews were celebrating a feast that set forth the pouring out of the Holy Spirit and thus Christ moves into speaking about the Spirit. Gill writes, "Which they that believe on him should receive; the apostles, and others, that had believed in Christ, and had received the Spirit, as a spirit of regneration and sanctification; as a spirit of illumination and conversion; as a spirit of faith and adoption; but on the day of Pentecost they were to receive a larger, even an extraodrinary measure of his gifts and grace, to qualify them for greater work and service:" Gill obvious believed and taught that the Spirit had indeed performed the work of regeneration in the apostles, however He was looking forward to Pentecost here in John 7, when the Holy Spirit would be poured out in open power and might!
Matthew Henry: "The Holy Ghost was not yet given in that visible manner that was intended, if we compare the clear knowledge and strong grace of the disciples of Christ themselves, after the day of Pentecost, with their darkness and weakness before, we shall understand in what sense the Holy Ghost was not yet given; the earnests and first-fruits of the Spirit were given, but the full harvest was not yet come. That which is most properly called the dispensation of the Spirti did not yet commence."
I hope this helps some!