Some think that God is always kind to people, while others think that He is always stern. The Bible says that He is both kind and stern at the same time, depending on our response to His promises.  Those who are trusting the Lord experience His kindness as He grafts them into the promises of Israel, and includes them in the family of God (Romans 11:17).  Those who continue to disbelieve experience His sternness as He cuts them off from God's family inheritance.

Paul appeals to the Gentile believers in the church in Rome (Romans 11:13-16) to consider how this dual nature of God affects them.  He is urging the Christians to choose to continue to live inside the boundaries of God’s kindness, into which they entered when they believed in Jesus.  He warns them that to depart from Jesus and all the grace which flows from Him would be disastrous.  He also warns them that they are no better than the Jewish-background believers; even though they may have previously spurned Jesus, when they believe they are also grafted back into the ‘stump of Jesse’ (a reference to King David’s spiritual line of faith in Isaiah 11:1).

True faith is not about passively accepting our cultural background, but actively believing the Word of God.  The Lord takes no delight when His people rebel, but He is still willing to receive back those who repent and believe His promise of salvation.  He is patient, longing that rebels repent and turn to Jesus as Saviour (2 Peter 3:9), but if they will not then judgement awaits the ungodly (2 Peter 3:3-7)

The Apostle Paul was convinced about the importance of responding positively to God's Word (James 1:22-25).  So he took great trouble to teach, explain, urge and persuade people to understand God's promised salvation in the gospel – so that the church might believe it and then be willing to take action upon it (the first action was usually baptism as in Acts 2:38).  The task of every disciple-maker includes making it clear that God demands an answer.  His kindness is waiting for those who believe and His sternness for those who persist in unbelief.  The Christian gospel is useless if it merely affirms the false delusion that God loves everybody and therefore all will be saved.  The gospel divides people according to their response; so its message must include a call to respond, along with its promise and warning.