Passage
And I will cleanse their blood, which I had not cleansed: and the Lord will dwell in Sion.
And I will cleanse their blood, which I had not cleansed: and the Lord will dwell in Sion.
Joel 3:19 Egypt shall be a desolation, and Edom a wilderness destroyed: because they have done unjustly against the children of Juda, and have shed innocent blood in their land.
Joel 3:20 And Judea shall be inhabited for ever, and Jerusalem to generation and generation.
Joel 3:21 And I will cleanse their blood, which I had not cleansed: and the Lord will dwell in Sion.
The verse centers on "cleanse", "blood", "cleansed", "lord", "dwell", and "sion". It is saying that the verse draws attention to "cleanse" and "blood", so its meaning should be read from those terms before moving to application.
The prior verse says "And Judea shall be inhabited for ever...", giving immediate footing for "cleanse" and "blood". In Joel context, the local focus is covenant, worship, and faithfulness.
A plain takeaway is to answer the verse's own emphasis on "cleanse" and "blood" with trust shaped by these words, not by a vague optimism outside the passage.