Charles Ellicott Commentary Jeremiah 51:50

"Ye that have escaped the sword, go ye, stand not still; remember Jehovah from afar, and let Jerusalem come into your mind." — Jeremiah 51:50 (ASV)

Ye that have escaped the sword ... — The words call on the people to fulfill the prediction of Jeremiah 50:4-5. Even in that distant land, afar off from the Temple of Jehovah, they are to remember that they are Israelites, and to think of Jerusalem as their home.

In Psalm 137:5-6 we have, as it were, by anticipation, the answer of the exiles. They had not forgotten Jerusalem in the revelry of their conquerors. They were not likely to forget her when their conquerors were, in their turn, conquered.