RobH_en_tn/isa/60/05.md

Then you will look and be radiant, and your heart shall rejoice and overflow

These phrases share similar meanings and emphasize that they will be very happy because of what will happen in Jerusalem. (See: rc://en/ta/man/translate/figs-parallelism)

the abundance of the sea

This refers to the riches and goods that will come to Jerusalem by way of shipping, perhaps from along the Mediterranean Sea.

be poured out to you

This describes that the abundance will be like water that gushes out. (See: rc://en/ta/man/translate/figs-metaphor)