Matthew Poole and continuators on Jeremiah 50:5

5 They shall ask the way to Zion with their faces thitherward, saying , Come and let us joyn our selves to the LORD in a perpetual covenant, that shall never be forgotten .

That is, those of Iudah and Israel that fear the Lord shall seriously and steadily seek the true God, and the true way of his Worship.

And being sensible that they had broken the Covenant which their Fathers had formerly made with God, with a desire to renew their Covenant, and that not for a time, but for ever. See chap. 31.31. The onely question is whether this promise be yet accomplished or no, or when it was, or shall be fulfilled? Answ. It was without doubt in a great measure fulfilled upon the Iewes coming out of the Captivity of Babylon, when those of the Kingdome of Iudah returned to Ierusalem, and were very zealous for restoring the true worship of God, and renewed their Covenant with God, (as we read in the books of Ezra and Nehemiah) but Mr. Calvin thinks it was more eminently fulfilled under the Kingdom of the Messiah, when though many believed not, yet many others did believe, and were added to the Church and whether a further fulfilling of it be not yet to come, time must shew.