This short epistle deals with one specific problem: the reception and aid of the brethren who will be passing through as they perform their deeds of ministry. In short, this epistle is about the importance of hospitality.
The Dispensation of the Grace of God
The distance between man and God is great. This is partly based on the greatness of God, but the distance is magnified even more by the lowliness of man.
Introduction to the Book of Ephesians
The children of Israel were to keep themselves separated from the other nations but, by intermarrying with the different nations around them, they had compromised and taken on their abominations. The answer for them, though it might seem harsh, was to separate from their heathen marriages.