KJV - Then shall ye call upon me, and ye shall go and pray unto me, and I will hearken unto you.
NLT -In those days when you pray, I will listen.
Call upon Me
Come to Me
Pray unto Me
From Matthew Henry's commentary:
This shall be in answer to their prayers and supplications to God, Jer. 29:12-15.
(1.) God will stir them up to pray: Then shall you call upon me, and you shall go, and pray unto me. Note, When God is about to give his people the expected good he pours out a spirit of prayer, and it is a good sign that he is coming towards them in mercy. Then, when you see the expected end approaching, then you shall call upon me. Note, Promises are given, not to supersede, but to quicken and encourage prayer: and when deliverance is coming we must by prayer go forth to meet it.