What ironies are present in lines 65-83 in Friar Laurence's speech in Act 4 Scene 5?

Friar tells Capulet that Juliet was going to go to Heaven some day so it might as well be now. The Irony here is that Juliet is really not dead yet. He also says it is best to marry well and die young which is rather ironic (dramatic irony) given that the audience knows these two will die by the end of the play (it's a tragedy, they have to!) .