I the LORD do keep it; I will water it every moment: lest any hurt it, I will keep it night and day.
Read Chapter 27
Ambrose of Milan
AD 397
You have in Isaiah the speech made by the soul of a just man or of the church: “I am a strong city, I am a city besieged,” defended by Christ and besieged by the devil. But one whom Christ aids ought not to be fearful of a siege. [Such a person] is defended by spiritual grace and is besieged by the perils of this world. Hence also it is said in the Song of Songs, “I am a wall, and my breasts are as a tower.” The wall is the church, and the towers are her priests, who have full power to teach the natural and the moral sciences. - "Six Days of Creation 6.8.49"
Therefore let us flee these evils and elevate our soul to the image and likeness of God. The flight from evils is the likeness of God, and the image of God is gained through the virtues. And so, like a painter, he has painted us with the colors of the virtues. “See, I have painted your walls, Jerusalem.” Let us not wipe away with the brush of neglect the props of the painted walls of our soul. And so “I have painted the walls,” with which we can turn away the enemy. The soul has its walls; from them it stands forth and concerning them it says, “I am a strong city, a city besieged.” By these walls it is guarded, and by them it is protected under siege. And truly the soul is a wall, which stretches forth over the camp. And therefore the bride says in the Song of Solomon, “I am a wall, and my breasts are like towers.” The wall that the Lord painted is good, even as he says: “On my hands I have painted your walls, and you are always in my sight.” - "Death as a Good 5.17–18"
It is the soul, too, that says, “I am a strong city, a city besieged.” The city is besieged through Christ, the city is that heavenly Jerusalem, in which there are interpreters of God’s law and men skilled in doctrine in great abundance; through them one seeks the Word of God. - "Isaac, or The Soul 5.39"
