Yes it is
The bemba idiom in contention draws it’s authority from the scripture which says “Do you not know that those men who are employed in the services of the temple get their food from the temple? And that those who tend the altar share with the altar in the offerings brought?”
And the next verse continues
In the same way, the Lord commanded that those who proclaim the gospel should get their living by the gospel.
The wise bembas who crafted this proverb meant to communicate what is in the scriptures above.
We have heard stories of how individuals have abused it in courts by quoting it in defense.The only reason they have quoted it’s because in its original meaning it’s very much acceptable except that taking things without owners knowledge or what is someone does not deserve is a criminal offense
The idiom can never lose its original meaning just because it has been abused or wrongly applied.
UBOMBA MWIBALA ALYA MWIBALA IS SCRIPTURE BASED IDIOM