From the Old Testament of the Bible, we have the ten commandments. We also have many other commandments sprinkled throughout the Bible. In the New Testament, Jesus introduced a few more commandments, especially those regarding loving one another.
Let's dive deeper into this.
Old Testament commandments include ones such as: Worship God only, keep away from idolatry, do not use God's name in vain, keep the sabbath, do not murder, do not steal, do not commit adultery, honor parents, do not bear false witness, do not covet (Deuteronomy 5), etc.
New Testament commandments include ones such as: do not be angry with your brother (Matthew 5:22), do not lust (Matthew 5:28), do not make an oath (Matthew 5:34), love your enemies (Matthew 5:44), forgive one another (Matthew 6:14), treat others the same way you want to be treated (Luke 6:31), pursue faith, hope and love (1 Corinthians 13:13), etc.
Many of the New Testament commandments are not simply external actions of what to do and what not to do. They are laws that govern the heart and attitudes within us.
So it's no longer enough to not commit adultery. But we need to not even look at anyone with lust. It is no longer enough to not commit murder. But we need to not even become angry or hateful against another person.
Jesus summarized the intent of all of God's commandments. He said, “ ‘You shall love the Lord your God with all your heart, and with all your soul, and with all your mind.’ This is the great and foremost commandment. The second is like it, ‘You shall love your neighbor as yourself.’ On these two commandments depend the whole Law and the Prophets.” (Matthew 22:37-40)
So everything from the Old Testament to the New Testament teaches us to love God with all of our being and to love people similar to how we love ourselves.
There is no real boundary or limit to God's laws, because there is no boundary for love.
There is also no boundary between the Old Testament laws and the New Testament laws. In fact, many laws from the Old Testament still apply. We are still not to worship other gods. We still should honor parents. We rest in God everyday. We should still not murder, commit adultery or steal.
Jesus fulfilled many laws we could not fulfill. For example, if we had coveted or disrespected parents, there was no animal sacrifice that could atone for these. In the Old Testament, only the sins that people committed unknowingly or unintentionally had sacrificial atonement (see Leviticus 4).
The punishment for sins committed knowingly was strict:
"Thus you shall not show pity: life for life, eye for eye, tooth for tooth, hand for hand, foot for foot." (Deuteronomy 19:21)
"If your brother, your mother’s son, or your son or daughter, or the wife you cherish, or your friend who is as your own soul, entice you secretly, saying, ‘Let us go and serve other gods’ (whom neither you nor your fathers have known, of the gods of the peoples who are around you, near you or far from you, from one end of the earth to the other end), you shall not yield to him or listen to him; and your eye shall not pity him, nor shall you spare or conceal him. But you shall surely kill him; your hand shall be first against him to put him to death, and afterwards the hand of all the people. So you shall stone him to death because he has sought to seduce you from the Lord your God who brought you out from the land of Egypt, out of the house of slavery. Then all Israel will hear and be afraid, and will never again do such a wicked thing among you." (Deuteronomy 13:6-11)
There was no begging for mercy, because justice was the way of Old Testament times.
When Jesus came, He fulfilled all the laws of God. And He did not sin.
Jesus said, "Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill. For truly I say to you, until heaven and earth pass away, not the smallest letter or stroke shall pass from the Law until all is accomplished." (Matthew 5:17-18).
"But He was pierced through for our transgressions,
He was crushed for our iniquities;
The chastening for our well-being fell upon Him,
And by His scourging we are healed.
All of us like sheep have gone astray,
Each of us has turned to his own way;
But the Lord has caused the iniquity of us all
To fall on Him." (Isaiah 53:5-6)
As the Son of God and Messiah, Jesus became the "Lamb of God who takes away the sin of the world!" (John 1:29). He became the ultimate sacrifice, so that all the laws are fulfilled through Him. Jesus died for our sins on the cross, because we cannot fulfill God's laws perfectly. By His righteousness and substitutionary death for us, we are made righteous before God.
If we believe in Jesus and repent and follow Him, God the Father extends His mercy to us. "If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness." (1 John 1:9)
So now, we are not put to death for our sins, because Jesus died in our place.
As believers in Christ, God also gives us the Holy Spirit to help us live for Him. We can obey God's commandments by asking for His help, and being diligent ourselves. God helps us to obey Him through His Holy Spirit who was given to us.