Hebrews 4:1 - 16
NKJV - 1 Therefore, since a promise remains of entering His rest, let us fear lest any of you seem to have come short of it. 2 For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them, not being mixed with faith in those who heard it.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
When the Holy Spirit lives in us He guides us by exposing areas of sinful thinking in our hearts and allows us to consider, either through His Holy Word, another believer etc., another more holy way of thinking that is more in line with the mind of Christ. Usually this is is something we never would have thought of outside of the guidance of God's Spirit.