I think that if a professing believer starts to fall away, the Holy Spirit will do a lot of work in him to correct and discipline him so that he will turn back to the path. But if the person stubbornly refuses to heed what the Holy Spirit is telling him, then God can leave him to his free will choice; but the Holy Spirit will not give up on him, and if he dies without coming back to faith and obedience, he could find himself in a lot of strife at the Judgment.
This way, both Scriptures are in harmony. God always allows us to have free will, but He provides revelation to make the gospel abundantly clear to every person, whether it is through His creation or through the preaching of the gospel. God's revelation first came through the written Scriptures, then His revelation came through the Person of Christ.
So, there does come to a point where after the Holy Spirit has done all he can to restore a person who has fallen away, where He has to release that person to their decisions made through their free will. But God remains faithful in continuing to make the revelation of His love, grace, and mercy through Christ continuing to be clear to anyone who has gone off the path and is falling away.