The "lack of knowledge" is the lack of knowledge of the difference between what is Holy and unholy and between unclean and clean. And this knowledge God has given to His spiritual priests on this earth today just as it was in the days of the Bible.
When Jesus was baptized by John the Baptist all our sins were passed onto Him in that moment in the Jordan River. This act between Jesus and John the Baptist fulfilled all righteousness. It saved us sinners who were heading to hell for our sins.
(Matthew 3:15, Romans 6:23)
This is the True knowledge of God's salvation for mankind that only His righteous servants preach.
(Malachi 2:6-7)
The law of truth was in his mouth,
And injustice was not found on his lips.
He walked with Me in peace and equity,
And turned many away from iniquity.
“For the lips of a priest should keep knowledge,
And people should seek the law from his mouth;
For he is the messenger of the Lord of hosts."
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