What is Denham's dentifrice Why is montag saying consider the lilies of the field?

I'm not quite sure, but this is what I think it means

The Lilies of the field is a passage from the Gospel of Matthew

It is, "And why do you worry about clothes? See how the Lilies of the Field grow. They do not toil or spin." He is trying to memorize this part of The Bible because just a paragraph before this he thinks to himself that he has to get every line in the Bible memorized. But the advertisement for Denham's Dentifrice (toothpaste) is stuck in his head.

Hope this helped