18.

That Noah was five hundred years old when God told him to make the ark, and six hundred when he entered the ark; which shows that the ark was made during one hundred years, which seem to correspond to the years of an age of the world. So the sixth age is occupied with the construction of the Church by the preaching of the gospel. The man who avails himself of the offer of salvation is made like a square beam, fitted for every good work, and forms part of the sacred fabric. Again, it was the second month of the six hundredth year when Noah entered the ark, and in two months there are sixty days; so that here, as in every multiple of six, we have the number denoting the sixth age.