Then shall they know that I {am} the LORD their God, which caused them to be led into captivity among the heathen: but I have gathered them unto their own land, and have left none of them any more there. {which...: Heb. by my causing of them, etc}
They will know that I am Yahweh their God, in that I caused them to go into captivity among the nations, and have gathered them to their own land. Then I will leave none of them captive any more.