The mortar in which the stones are set is made of lime, sand, and water. Lime is fervent love, which takes to itself the sand, that is, earthly toil; then water, which is the Spirit, unites the lime and sand. As the stones of the wall would have no stability without the mortar, so men cannot be set in the walls of the heavenly Jerusalem without love, which the Holy Spirit brings. The stones of the wall are hewn and squared, which means sanctified and made clean. Some stones are borne, but do not themselves bear any burden, and these are the feeble in the Church. Other stones are borne, yet also bear; while still others bear, but are not borne, save by Christ alone, the one foundation; and the last are the perfect. The Jews were subject to hostile attack while building the walls of Jerusalem,[87] so that with one hand they set stones, while they fought with the other. Likewise are we surrounded by hostile vices as we build the walls of the Church; but we oppose them with the shield of faith and the breastplate of righteousness, and the sword of the Word of God in our hands. The church edifice is disposed like the human body. The chancel, where the altar is, represents the head, and the cross (transept) the arms and hands. The western portion (nave and aisles) is the rest of the body. But indeed Richard of St. Victor deems that the three parts of the edifice represent in order of sanctity, first the virgins, then the continent, and lastly married people. Again, the Church is built with four walls; that is, by the teaching of the four evangelists it rises broad and high into the altitude of the virtues. Its length is the long-suffering with which it endures adversity; its breadth is love, with which it embraces its friends in God, and loves its enemies for His sake; its height is the hope of future reward. Again, in God’s temple the foundation is faith, which is as to what is not seen; the roof is charity, which covers a multitude of sins. The door is obedience--keep the commandments if thou wilt enter into life.[88] The pavement is humility. The four walls are the four virtues, righteousness, (_justitia_), fortitude, prudence, and temperance. The windows are glad hospitality and free-handed pity. Some churches are cruciform, to teach us that we are crucified to the world, or should follow the Crucified. Some are circular, which signifies that the Church is spread through the circle of the world.