One of my friends asked this question, after seeing these memes:
“The Old Testament laws and penalties contradict the law of Christ to love God and love each other as our self. You cannot believe what Christ says of loving our enemies, going the extra mile and being a good samaritan, and entering an enemies town as in the OT and killing every man, woman and child. That sort of thinking and living is no better than todays Islamic radicals. The Roman Catholic Church put together the books authored by patriarchs, prophets, kings, disciples and apostles of which today we call the Bible. There is obviously a progression of theology and law throughout Biblical times and it continues today. Loving God, and loving each other. Everything else is not as important. Interesting, but not a relevant.”

My response, to explain these things, using scripture:

You are referring to Matthew 22:37-39.
I know this well.

37 Jesus replied, “‘You must love the Lord your God with all your heart, all your soul, and all your mind.’[e] 38 This is the first and greatest commandment. 39 A second is equally important: ‘Love your neighbor as yourself.’

However, I believe you are a victim of false doctrine.
To understand verses 37-39, you have to look at verse 36.

36 “Teacher, which is the most important commandment in the law of Moses?”

Jesus is not creating New Testament doctrine. He is simply answering a question about the Torah, the law already given. In fact, if you research it, you’ll find that Jesus is actually QUOTING the law.
Verse 37 is a quote from Deuteronomy, and verse 39 is a quote from Leviticus.
Seriously!! Look it up!!

Just in case we are confused by false teaching and false beliefs, Jesus tells us what He is saying in verse 40.
40 The entire law and all the demands of the prophets are based on these two commandments.”

He tells us these “two commands” are just paraphrasing the law and the prophets.

As for entering into lands and killing…
This is impossible to understand if you have not come to a full understanding of what is written before.

Genesis 3:15 and Genesis 6 tells establishes why Noah’s flood and killing those in the promise land were necessary.
In Numbers 13, we see confirmation as to why this was necessary.

In Genesis 6, we see that rebelious fallen angels took human wives for themselves (against the will of God) and their offspring created the Nephilim, a breed of giants. Scripture validates this (Job establishes that these were fallen angels, not men in Gen 6:4).
Og of Bashan, Goliath, and many other references to giants throughout scripture establish this as truth.

Numbers 13 tells us that Joshua, Caleb, and the other 18 spies witnessed these giants living in the land. They were as grasshoppers in their sight.

Fallen angels corrupted the Creation of God. Noah’s flood cleansed the earth of them. You’ll see in Gen 6:9 that Noah was chosen because he was a righteous man AND ALSO because he was perfect in his generations. It was spiritual (righteous) and physical (perfect in his generations, or genetics).

This may sound crazy to you because mainstream Christian doctrine won’t touch these ideas with a ten foot pole.
But they are all right there in scripture, in black and white.

If you are interested, I can explain these thing to you in greater detail, using scripture (not my ideas).

We are told by Jeremiah that a time will come when Gentiles realize they have inherited nothing but lies.
That time is now.

Jeremiah 16:19-20
O Lord, my strength and my fortress,
My refuge in the day of affliction,
The Gentiles shall come to You
From the ends of the earth and say,
“Surely our fathers have inherited lies,
Worthlessness and unprofitable things.”
20 Will a man make gods for himself,
Which are not gods?

The church teaches a concept of a mean old God in the Old Testament, and a kinder, gentler deity of Jesus in the New Testament.

Messiah Himself tells us that He and the Father are one.
He tells us his doctrine is not His own, but the Father’s who sent Him.
Numbers and Micah tell us that God is not a liar and does not change His mind. John 1:14 tells us that Jesus is the Word become flesh. Hebrews 13:8 tells us that Jesus is the same yesterday, today, and forever.
If He is the word and He never changes, then the word never changes.

There are clues all through scripture to tell us that nothing has changed since day one.
God said His instructions in Torah are forever, perpetual, never ending, and for all generations.
Believing that the law is no longer applicable makes God a liar, which is impossible. (Pus scripture tells us God cannot lie).

Mainstream doctrine has twisted scripture so badly that no one knows the truth.
But it is all right there on the pages, waiting for us to read it.
Churches mostly use the writings of Paul to back up and ‘prove’ their doctrine.
We are warned against using Paul’s writings the way the church uses them:

2Peter 3:14-18
Therefore, beloved, looking forward to these things, be diligent to be found by Him in peace, without spot and blameless; 15 and consider that the longsuffering of our Lord is salvation—as also our beloved brother Paul, according to the wisdom given to him, has written to you, 16 as also in all his epistles, speaking in them of these things, in which are some things hard to understand, which untaught and unstable people twist to their own destruction, as they do also the rest of the Scriptures.

17 You therefore, beloved, since you know this beforehand, beware lest you also fall from your own steadfastness, being led away with the error of the wicked; 18 but grow in the grace and knowledge of our Lord and Savior Jesus Christ.

To Him be the glory both now and forever. Amen.

He warns us to not go the way of the lawless, which will result in our destruction.
Messiah tells us the exact same thing in Matthew 7:21-23.
Depart from me, you workers of lawlessness.

Revelation tells us who the remnant of the church is:
Rev 12:17
And the dragon was enraged with the woman, and he went to make war with the rest of her offspring, who keep the commandments of God and have the testimony of Jesus Christ.

Those who keep the commands of God and have faith in Jesus!!
Two things, not one.

Rev 14:12 tells us who the saints are (the elect, the saved):
Here is the patience of the saints; here are those[g] who keep the commandments of God and the faith of Jesus.

Again, two criteria!! Not one.

The words of Messiah Himself tell us who gets to be in His kingdom in Rev 22:14.

Blessed are those who do His commandments,[g] that they may have the right to the tree of life, and may enter through the gates into the city.

Again in Revelation, we are told for the third time to keep the commandments, this time by Messiah Himself.

In Rev 22:15, He tells us who will not be in His kingdom:
15 But outside are dogs and sorcerers and sexually immoral and murderers and idolaters, and whoever loves and practices a lie.

Those who love and practice a lie will not be in the kingdom.
What lies?
Refer to the prophecy of Jeremiah again:
“Surely our fathers have inherited lies,
Worthlessness and unprofitable things.”

It specifically says that Gentiles will realize we have inherited lies.
If those people continue to love and practice those lies, they will not be in the kingdom.

No my words, but God’s (through Jeremiah) and the words of Messiah to confirm it.

If you’d like to know more about these things, I’d be happy to share scripture with you that explains them in more detail.