Why did Gandalf save Faramir?

[MatthewM]

Originally Posted by Guinevere

So he clearly thought, that Faramir was important for Gondor. He is not only noble (Somewhere it is stated that "the blood of Numenor runs more true in him than in Denethor or Boromir" but I can't find the quote right now.) but he is also wise and compassionate, and the people of Minas Tirith love him.

I don't have the quote handy, but I'm almost positive that Denethor was not included in Tolkien saying that, I believe it was just Boromir it did not run "truly" in...which I always found to be rather annoying, bias, and selective...not to mention almost hereditarily impossible.