Greeting brother & sister in Christ,
The Old Testament is as important as the New Testament, but Jesus changed a few things, this does not make the OT irrelevant, but we must note the differences.
God ruled, with what seems an iron stick approach. We see the Blessings the Jews received when they obeyed God's commands, we see, as you rightly say the punishments that God dealt them. I feel so much for the Jews, punished by man, punished by God, and punished quite harshly at times (It may seem).
But then the Christ came, love came down at Christmas we say, and it certainly did. But Jesus came to save those who were lost, and God showed His love in a different way, 'For God so Loved the world he had created...' Everything Jesus did and said was based on Love, the Father's Love, his message from start to finish is base on Love, his instructions to Jews and Gentiles alike are based on Love.
John 13:34-35 (NKJV)
34 A new commandment I give to you, that you love one another; as I have loved you, that you also love one another.
35 By this all will know that you are My disciples, if you have love for one another."
Luke 6:27-31 (NKJV)
27 "But I say to you who hear: Love your enemies, do good to those who hate you,
28 bless those who curse you, and pray for those who spitefully use you.
29 To him who strikes you on the one cheek, offer the other also. And from him who takes away your cloak, do not withhold your tunic either.
30 Give to everyone who asks of you. And from him who takes away your goods do not ask them back.
31 And just as you want men to do to you, you also do to them likewise.
And many more verses as we know. But what about the Law?
Matthew 5:17-20 (NKJV)
17 "Do not think that I came to destroy the Law or the Prophets. I did not come to destroy but to fulfill.
18 For assuredly, I say to you, till heaven and earth pass away, one jot or one tittle will by no means pass from the law till all is fulfilled.
19 Whoever therefore breaks one of the least of these commandments, and teaches men so, shall be called least in the kingdom of heaven; but whoever does and teaches them, he shall be called great in the kingdom of heaven.
20 For I say to you, that unless your righteousness exceeds the righteousness of the scribes and Pharisees, you will by no means enter the kingdom of heaven.
We are saved by Grace through Faith, but this does not abolish the Law. We are in the age of God's Grace, we are also in the age of His Love through Jesus.
The Law is not abolished, till heaven and earth pass away, one jot or one tittle will by no means pass from the law till all is fulfilled.
This tells me the Law will remain until heaven and earth pass away, not one jot or tittle will pass from the Law, but...
Then the Christ came. Jesus came to save those who were lost, God showed His love in a different way, 'For God so Loved the world he had created...' Everything Jesus did and said was based on Love, the Father's Love, his message from start to finish is base on Love, his instructions to Jews and Gentiles alike are based on Love.
And it is all included here...
John 13:34-35 (NKJV)
34 A new commandment I give to you, that you love one another; as I have loved you, that you also love one another.
35 By this all will know that you are My disciples, if you have love for one another."
The Law still applies but is based on 'The New Commandment' LOVE.
Thou shalt not, still applies, the Law still applies based on Love, so stoning to death and similar OT commands are no longer acceptable, they cannot be done in Love.
Because the Father and the Son love us with an infinite and perfect love, and because we cannot see what they see and know. They have given us laws that will guide us, protect us and reveal sin to us, so that we may seek to become righteous.
There is a strong connection between God’s love and His laws, there is a strong connection between Jesus' Commands of the Fathers Love for one another and the laws. I feel that the Law makes more sense when seen in the eyes of Love, when seen in the eyes of God through Jesus.
Grace, mercy, and peace will be with you from God the Father and from the Lord Jesus Christ, the Son of the Father, in truth and love.
Shalom