"These violent delights have violent ends and in their triumph die, like fire and powder, which as they kiss, consume. Therefore, love moderately; long love doth so."
speaker: Friar Laurence
meaning: Emotions like love that are so extreme that they take over everything, will end badly at their peak, like fire and powder that destroy one another. So, take things slowly because then the love will last
Friar's advice: Slow down, take time, theses extreme emotions won't last.
*"violent delights"=oxymoron, "which as they kiss consume"-kiss=personification