From the first covenant of the Bible, we have the ten commandments. We also have many other commandments as well.
The ten 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, and do not covet (Deuteronomy 5).
Besides these commandments, there are over 600 commandments that God gave, which are written throughout the Old Testament (or Old Covenant).
Many of these commandments are ceremonial or for the temple and priests. Today we don't have the temple or priests who can minister and make sacrifices. So many of these laws cannot be kept.
It is very difficult (if not impossible) to keep all these commandments. Even simply abiding by the ten commandments and not sinning at all is impossible.
Have you used God's name in vain in your life? Have you coveted or desired anyone else's possessions? Have you ever idolized any humans, or put anything on a high pedestal in your heart? Have you ever fought with your parents or disrespected them in any way when you were young?
God's law says that if we fail in even one of these commandments one time, we are guilty.
“For as many as are of the works of the Law are under a curse; for it is written, ‘Cursed is everyone who does not abide by all things written in the book of the law, to perform them.’ Now that no one is justified by the Law before God is evident; for, ‘The righteous man shall live by faith.’ However, the Law is not of faith; on the contrary, ‘He who practices them shall live by them.’” (Galatians 3:10-12)
One of the reasons God gave all these commandments was to show that God’s standards are very high and perfect. These commandments serve as a tutor for us of how we should live. However, to perform them perfectly is impossible. The commandments show that we need a savior to save us from our sins.
We know there are two ways for a person to live before God forever.
By keeping all the law, or
By faith and repentance
We know that as fallible humans we cannot possibly keep all the law all the time. When we fail to keep all the law, it is sin. The penalty for sin is death and eternal punishment. But there is a second way to salvation and forgiveness.
The second way is by faith and repentance. This concept is not new, but it began in the Old Covenant itself.
“Then he [Abraham] believed in the Lord; and He reckoned it to him as righteousness.” (Genesis 15:6)
Furthermore, the prophet Habakkuk said:
“Behold, as for the proud one,
His soul is not right within him;
But the righteous will live by his faith.” (Habakkuk 2:4)
So the way to salvation by faith was introduced in the Old Covenant. And God gave the New Covenant to us so that this could be fulfilled.
The New Covenant is the covenant in the blood of Jesus, who is the Son of God and Messiah. Old Covenant sacrifices could not atone for sins adequately.
The prophet Micah highlighted this fact:
"Does the Lord take delight in thousands of rams,
In ten thousand rivers of oil?
Shall I present my firstborn for my rebellious acts,
The fruit of my body for the sin of my soul?" (Micah 6:7)
Jesus is the Son of God who is perfect and never sinned. He came to earth to die for us and He became the perfect sacrifice. He 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 keep God's commandments perfectly. But Jesus kept God's commandments perfectly. By His righteousness and substitutionary death for us, we can be made righteous before God the Father and have eternal life.
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)
"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)
Isaiah prophesied in the Old Covenant that the Messiah would be pierced for our sins. Jesus was pierced on the cross for us. Because of His sacrifice, we can be forgiven and made right with God. If we believe in Jesus, we can have eternal salvation through Him.
When Jesus came, He made the New Covenant with us so that we can be fully reconciled to God the Father. Jesus also paid retroactively for those who believed in God and hoped for a Messiah during Old Covenant times.
So everyone can be saved and perfected through Jesus.
Jesus said, "I am the way, and the truth, and the life; no one comes to the Father but through Me." (John 14:6)
"For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life. For God did not send the Son into the world to judge the world, but that the world might be saved through Him." (John 3:16-17)