“Now after John was put in prison, Jesus came to Galilee, preaching the gospel of the kingdom of God, 15and saying, “The time is fulfilled, and the kingdom of God is at hand. Repent, and believe in the gospel.” (Mk 1:14,15)
“Repent,” The basic meaning of repent (Gk metanoeite) is “to change your mind”—not superficially, but changing your basic attitudes and lifestyle. It involves a change of masters: from sin and Satan being master to Jesus Christ and His Word being Master (cf. Acts 26:18; Rom 6:19, 22; Eph 2:2). Repentance is often connected with epistrephein, “to turn,” as in repenting, turning to God and proving one’s repentance by the fruit of a changed life (Acts 26:20; cf. Acts 3:19). The saving faith that the grace of God makes possible in response to hearing the gospel includes repentance (Mark 1:15; Luke 13:3, 5; Acts 2:38; 3:19; 11:21). To define saving faith in a way that does not involve a radical break with sin distorts the Biblical view of redemption. Repentance is a free decision on the part of sinners, made possible by the enabling grace given to them as they hear and believe the gospel (Acts 11:21).
The definition of saving faith as “mere trust” in Christ as Savior is wholly inadequate in the light of Christ’s demand for repentance. To define saving faith in a way that does not necessarily involve a radical break with sin is to dangerously distort the Biblical view of redemption. Faith that includes repentance is always a condition for salvation (cf. Mark 1:15; Luke13:3, 5; Acts 2:38; 3:19; 11:21). Repentance was a basic message of the OT prophets (Jer 7:3; Ezek 18:30; Joel 2:12-14; Mal 3:7), John the Baptist (Mat 3:2), Jesus Christ (Mat 4:17; 18:3; Luke 5:32) and NT Christians (Acts 2:38; 8:22; 11:18; 2 Pet 3:9). The preaching of repentance must always accompany the gospel message (Luke 24:47).
Difference between true and false repentance
“For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death.” (2 Cor 7:10)
“godly sorrow ... sorrow of the world”. Paul identifies two kinds of sorrow here. (1) There is a genuine sorrow for sin that leads to repentance, i.e., a change of heart that causes us to turn from sin to God. This type of repentance leads to salvation. For Paul, repentance from sin and faith in Christ are human responsibilities in salvation (see Mat 3:2). (2) In contrast, the unrepentant often become sorry only for the consequences of their sin; such sorrow results in eternal death and judgment (Mat 13:42,50; 25:30; Rom 6:23).
What does it mean to “believe in the Lord Jesus Christ”?
Read Acts 16:25-34. The Philippian jailer converted
“And he brought them out and said, “Sirs, what must I do to be saved? 31So they said, “Believe on the Lord Jesus Christ, and you will be saved, you and your household.” (Acts 16:30,31)
16:30 “What must I do to be saved?” This is the most important question one can ask. The apostles’ response is, “Believe on the Lord Jesus” (v. 31). (1) To believe in the Lord Jesus is to focus our faith and commitment on the person of Christ. It means turning to Him as a living person who is our Redeemer from sin, our Savior from damnation and the Lord of our lives. It means believing that He is the Son of God sent by the Father and that all He said is true and authoritative for our lives.