AP Euro: DBQ Essay help! Please Help?

I'm writing a DBQ Essay and i'm having trouble with one of the documents:

"I well know, that as you are now to reside in Rome, that sink of all iniquity, the difficulty of conducting yourself by these admonitions will be increased. The influence of example is itself prevalent; but you will probably meet with those who will particularly endeavor to corrupt and incite you to vice; because, as you may yourself perceive, your early attainment to so great a dignity is not observed without envy, and those who could not prevent your receiving that honor will secretly endeavor to diminish it, by inducing you to forfeit the good estimation of the public..."

it's a letter from Lorenzo di Medici to Giovanni di Medici after his promotion to Cardinal at age 14. can anyone tell me what he's saying in the quote and how it's significant to causes of the Protestant Reformation?

any info would be greatly appreciated!