15 Dec - Hebrews 9
I think Hebrews 9 sums up that entire feeling of Maranatha.
It reminds us that before Jesus, there was such a massive faff to get right before God. Sacrifices to make, sins to confess, the priest only being allowed into the holy of holies once a year, and only if he had make the right sacrifices. This is how God's people used to interact with Him. You can understand why they would cry, perhaps unknowingly, Come Messiah, Come.
And then the hinge comes in v11, 'But when Christ came.' That when he came as the perfect person he was able to demolish that need to make sacrifice. And the people are able to approach God. Not by going into the holy of holies, but because Jesus went to the perfect temple and made the whole earth His temple, His dwelling place.