Assurance: Unpardonable sin!
One of the devil’s temptations whispered to many a new Christian is the temptation to believe they have committed “the unpardonable sin,” and thus they are beyond God’s saving grace. Doomed to be damned.
Perhaps they have read passages where Jesus warns of this sin; there are two:
“And so I tell you, every kind of sin and slander can be forgiven, but blasphemy against the Spirit will not be forgiven. Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.” (Matt. 12:31-32).
“’Truly I tell you, people can be forgiven all their sins and every slander they utter, but whoever blasphemes against the Holy Spirit will never be forgiven; they are guilty of an eternal sin.’ He said this because they were saying, ‘He has an impure spirit.’” (Mark 3:28-30).
The Pharisees had just accused Jesus of casting out demons by Beelzebul, the prince of demons. In other words they were saying that Jesus’ power to do miracles came not from God but from the devil. They were refusing to accept the Holy Spirit’s witness as to Who Jesus was and to bow to Him as Lord.
When a person does this they turn away from the convicting voice of the Holy Spirit… they choose not to hear His call, consequently they become unable to respond to it. Of this sin Billy Graham says,
“While there is an unforgivable sin, it is not one that a true believer in Jesus Christ can commit… if we have received Jesus as our Savior and Lord, we have not blasphemed the Holy Spirit; we have accepted His witness. …the unpardonable sin is not some particularly grievous sin committed by a Christian before or after accepting Christ, nor is it thinking or saying something terrible about the Holy Spirit. Rather, it is deliberately resisting the Holy Spirit’s witness and invitation to turn to Jesus until death ends all opportunity.” – Billy Graham
In short, as long as you want Christ as Lord and Saviour you will be able to give yourself to Him. But persistent refusal to respond to His convicting Voice can harden your heart till you no longer hear Him, no longer seek Him. In short, you do not want Him — like the Pharisees.
In Hebrews we read,
“If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, but only a fearful expectation of judgment and of raging fire that will consume the enemies of God.” (Heb. 10:26-27).
This is why scripture pleads “Today, if you will hear His voice, Do not harden your hearts…” (Heb. 3:8).
But the believer whose heart is not hardened but tender, touched by the love and grace of Christ, who desires God and seeks more of Him, this person may rest assured in Christ knowing the temper’s lie that they have committed the unpardonable sin is just that – a lie.