To these Jewish leaders Stephen said, "Ye do always resist the Holy Ghost." So here were people some of whom had seen Jesus and heard Him preach, others who had heard Peter the apostle at Pentecost, others who had heard Stephen and other Spirit-filled men preaching with great power so that "the word of God increased; and the number of the disciples multiplied in Jerusalem greatly; and a great company of the priests were obedient to the faith" (Acts 6:7). And what had these done? They were stiffnecked and uncircumcised in heart and ears, that is, they were stubborn in their rebellion against God. They were deliberately "uncircumcised in heart and ears," remaining unconverted. And this resistance against the Holy Spirit went to such length that as they heard Stephen preach, "they were cut to the heart, and they gnashed on him with their teeth," and then they took him out of the city and stoned him and killed him! Men did resist the Holy Spirit. These particular men had done so year after year under great moving of the Holy Ghost.
And Stephen said, "As your fathers did, so do ye." So Stephen says that all the way from Abraham through the history of the Jewish nation down to the time of Christ and those same Jewish elders, unconverted Jews had resisted the Holy Spirit!
Thus we must believe, taking the Word of God at face value, that God calls people who do not come. God convicts people who will not repent. God's Spirit moves people to be saved, but they will not be saved.
One of these same Jewish leaders who heard Stephen speak was Saul of Tarsus. Oh, how he hated this new sect of Christians! And now with that hate flaming in his heart and the zeal of Judaism he set out to arrest Christians at Damascus. You see, Paul up to this time was resisting the Holy Ghost, so much so that later God said to him, "It is hard for thee to kick against the pricks" (Acts 9:5). So people do kick against the pricks of God's Holy Spirit. People do resist the call of God. People do resist God's grace and do thwart God's offer of mercy. And that means that those who are not saved could have been saved. Those who reject Christ could have accepted Him. God offers mercy to those who will not have it. Those who go to Hell go, not because God wanted them to go, nor because they were predestined to go to Hell, but they go to Hell because they would not heed the moving of the Holy Spirit on their hearts, and they would not repent when God commanded them to repent. They would not follow the light that God gave them.
Again in Hebrews 10:29 we find the clear statement that men resist God, that sometimes men who are convicted and moved to get saved will not be saved.
Read Hebrews 10:28 and 29 together. "He that despised Moses' law died without mercy under two or three witnesses: Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?"