1. How did God build on his existing standards?

In the new testament, God sent Jesus, God himself, to come to the world (John 1). Jesus built on the Old testaments foundation, (Matt 5:17-20). Besides the emphasis on keeping the words and physical requirement of the law. (Jesus wanted his believers to have righteousness that exceed that of the scribes and pharisees.) . Jesus emphasise on the heart behind the actions. Now murder begins when you hate the person, adultery happens when you think lustful. (Matt 5:17-27)

Sabbath is more than just not working and listening to the words of God. Jesus expects his believers to do good on sabbath (Matt 12:1-14).

In this view, it would be clear that Jesus built the new testament by increasing the depth of the old testament. Which goes beyond the physical actions, but now it emphasise on the heart and mind of keeping the law. The new testament believers are to follow the word of God out of their love for God, not because of the fear of punishment.

2. How does God forgive sins in the new testament? God first did the ultimate sacrifice for sin, by taking on the punishment that man is suppose to suffer as the result of sin, death. He bled and allowed his blood to be the ultimate sacrifice for sin. (John 3:16)

God established baptism for the remission of sin (Acts 2:38). He stresses on having faith in the grace of Jesus, a heart of repentance as well as the physical action doing it. ( Eph 2:8-9, Jas 2:18-24). Baptism, Holy Communion, foot washing is made effective by the grace of Jesus, given when he is nailed on the cross, as well as our faith in his words (the bible), and our obedience to follow it.

Baptism and foot washing is conducted once in the lifetime, with its effects lasting through the entire life of the believers. Holy Communion serves as a time for Christians to reflect their relationship with God, examine themselves of their sins, and to ask God forgiveness and who would remember our sins no more (1 Cor 11:27-34). This is the reason for the Apostles warning not take the Holy Communion lightly, in Corinth, there are Christians who take Holy Communion seriously and died (1 Cor 11:30).

Jesus knows, with depth of the law of God deepened, it would be even harder for the new testament believers to follow the commandments of God (just think about the old testament saints and their difficulty keeping the old testament). Therefore God has decided to stay in the heart of believers, giving his spirit to guide the new testament believers to understand truth (John 16:5-15). The holy spirit will work with our conscience to warn members when they are about to sin, as well as to be their counsel and comforter to encourage them to follow the will of God (John 14: 15-18)

At the same time, God allowed himself to be our mediator in heaven(Heb 9:11) to allow Christians to come to him easily for the forgiveness of sin.

Jesus, being human, and knowing our weakness as human being, is able to have compassion and intercede for us all the time. This is because he had taken a form of a man and he understand our weakness and our inability to handle the many temptations and trials. (Heb 4:14-16). He open a way through his blood to allow believers to come to God for forgiveness of sin easily.

In fact, in the daily road Christian walks, when a Christian sins, Gods grace aboundeth more and to forgive them. (Rom 5:19-21)

3. What is does God want Christians of the new testament to do?

Since the forgiveness of sin is freely given, God wanted Christians not to abuse this forgiveness for indulging ourselves with sin. (Rom 6:1-4, 15). Instead, Jesus wanted the believers to walk in newness of life, lead a life free of sin, with the help of the Holy Spirit (Col 2:6). God doesn’t want Christians to look lightly on this grace that he had given, through the death of Jesus, hence Christians should not just fall away or turn apostate are crucifying God the second time (Heb 6:4-6).

Christians must lead a life of spiritual nurture, to help them to follow Gods commandments better. (Heb 6: 1-3). The main goal of spiritual nurture is to train a Christian put on Christ to imitate Christ (1 Cor 11:1). To achieve this, Christian needs to spend time in pray to God (Acts 2:42). Prayers are important as it is an important channel of communication to God, and God does comfort using the Holy spirit to the members. Besides prayer,
meditating on the words of God is important(Php 4:8-9, 2 Tim 3:15-16). The words of God will only be put into actions when a Christian learn to serve God.

it is indeed true, that within a Christians lifetime, it would be difficult to reach the stage to be 100% like Christ. So that is the reason why God is gracious, and made Christian righteous through his blood. Not that because they are perfect, but because they have placed their faith in God. He renewed Christians daily, forgiving them, encouraging them to continue their fight through prayers and the word of God. (Col 3:1-11)

This is difficult, thats why Paul compared his Christian walk is liken to the race for the prize and just when he was just about to die, i said "I have fought the good fight, I have finished the race.. " (2 Tim 4:6-8)

4. Are there sins that are unforgivable?

Alot of times, Christians tend to stay away from this topic. Actually, there are sins that will never be unforgivable. There are 2 in particular I would like to highlight.
1. Blasphemy against the Holy spirit ( Lk 12 : 10, Mk 3:29)
2. Even Elder John talks about Sin leading to death (1 Jn 5:16-17) out of which the most evident ones are
a. Preaching heresy (1 Tim 1:18-20)
b. Sinning wilfully (Heb 10:26)
3. The church does has the power to excommunicate members, although I believe the church should practise prudence when exercising this authority(Matt 18:15-21)

5. Conclusion

For the three blog post, we have discussed on many things
1. Sin is falling short of the standard of God
2. God establishing his standard in the OT (like a tutor) and then deepen the standard in the NT
3. At the same time, because of the deepening of the standard, Jesus came to offer his life as a sacrifice, so man can come to God easily for forgiveness
4. God expects man to try his best to imitate Christ, so Christians should combat sins by daily spiritual nurture. Prayers, reading and mediating on Gods work and serving God and the church are the basic steps to spiritual nurture

It is hope that from here, we would gain the strength to make use of Gods grace, to finish our race of faith.

Here are all the blogs in this series

Sin and Forgiveness (Part 1/3): What is sin and their effects?
Sin and Forgiveness (Part 2/3): The Old Testament
Sin and Forgiveness (Part 3/3):The new testament and conclusion