Jesus' last words to the world are found in Revelation 22:18-20. In Revelation 22:18-19, Jesus issues a warning to those who would tamper with God's Words. The reason is because God is love. He loves all people even if they do not love Him. He desires all people to come to salvation. He does not want them to experience His judgment.
Jeremiah the prophet preached God's Word to Judah for 40 years. His preaching was ignored. He reminded the Jewish nation of God's warnings about disobedience to His word found in the Old Testament. But the nation's religious and political leaders did not repent of their sin. The example of these unrepentant leaders influenced the way the citizens of Judah lived. The end result was national sin which resulted in God's judgment, seen in the Babylonian captivity. This is an example to all future nations. If God's Chosen People would suffer consequences for disobeying God, we can be certain that all other people groups will also suffer for the same reason.
The importance of any nation to live in accordance with God's standards cannot be overstated. That is why Jesus' final words in the Bible were a warning to man not to tamper with God's Word. It was motivated by His love for man, nothing more.