“They went forth together from Ur of the Chaldeans.”
The rabbis tell us that the name ‘Ur’ (‘ur) is related to the word for ‘light’. Abraham was ‘tried in the fire’ of the Chaldeans, just as his later descendants, the Three Young Men spoken of in Daniel, were tried in the fires of idolatrous Babylon in the days of the Exile. Abraham, our ‘father in faith’, foreshadowed Israel’s return to the Holy Land. He, too, departed from the gods of Babylon/Chaldea to follow the promptings of the One God.
The way of faith is a way of darkness. To go forth from Ur is to go forth from the light of the earthly senses into the darkness of the purgative way. Abraham now ‘walks by faith and not by sight’ [2 Cor 5: 7], journeying ‘by paths they never knew’ [Is. 42: 16], allowing God to ‘turn the darkness before them into light.’