Well, you are not quoting the entire verse
(Which sends an entirely different and wrong kind of message).
Here is the entire verse in what it says,
"
I came not
to call the righteous, but
sinners to repentance."
(Luke 5:31).
For obviously even those believers who believe we should live holy and righteously in this life were once sinners who had repented of their sins. Jesus is not talking about how we will remain as sinners. Jesus said he calls sinners to
repentance. How can we know what repentance looks like? Jesus defines repentance for us so we cannot change it into something we prefer. Jesus said, "The men of Nineveh shall rise in judgment with this generation, and shall condemn it: because they repented at the preaching of Jonah" (Matthew 12:41).
If we were to turn to Jonah chapter 3, we would read this,
8 "But let man and beast be covered with sackcloth, and cry mightily unto God: yea, let them turn every one from his evil way, and from the violence that is in their hands.
9 Who can tell if God will turn and relent, and turn away from his fierce anger, that we perish not?
10 And God saw their works, that they turned from their evil way; and God relented of the disaster, that he had said that he would bring upon them; and he did it not."
(Jonah 3:8-10)
Did you catch what it said?
Verse 8 says - that the king of Nineveh declaring to his people to be covered in sackcloth, cry unto God mightlily unto God, and turn from their evil and wicked ways.
Verse 10 says - God saw their works and that they turned from their evil ways and God changed His plans in regards to the type of wrath that He was going to bring upon them.
This is all too clear that this is an example of repentance and the fruits thereof.
....