We should be on guard against wickedness and evil that spring up in our minds. We must guard our thoughts against all sorts of sin. Most sins, if not all of it, begin with thoughts. If we can keep our minds under the control of the Holy Spirit, we will go a long way towards becoming holy.
7 The Holy Spirit says: “Oh, that today you would hear his voice, 8 “Harden not your hearts as at the rebellion in the day of testing in the desert, 9 where your ancestors tested and tried me and saw my works 10 for forty years. Because of this I was provoked with that generation and I said, “They have always been of erring heart, and they do not know my ways.” 11 As I swore in my wrath, “They shall not enter into my rest.” ’ ” 12 Take care, brothers, that none of you may have an evil and unfaithful heart, so as to forsake the living God. 13 Encourage yourselves daily while it is still “today,” so that none of you may grow hardened by the deceit of sin. 14 We have become partners of Christ if only we hold the beginning of the reality firm until the end.