In Romeo and Juliet, what do the quotes "The heavens do lour upon you for some ill. / Move them no more by crossing their high will" (4.5) and "A greater power than we can contradict / Hath thwarted our intents" mean? Please close-read and summarize.

The context for these lines is the "death" of Juliet. After discovering Juliet's lifeless body in her chamber, Lord Capulet and his wife are understandably distraught. Friar Laurence enters and immediately tries to console the parents by telling them that Juliet has entered a state far better than that she would have entered into by marriage. He tells them to prepare the body for burial. The lines in question are interesting ones, because when he says that the "heavens . . . lour" upon the Capulets for "some ill," he is saying that Juliet's death is obviously some kind of punishment from God. The "heavens" have figuratively "lowered" on the house of Capulet. He urges them to bury Juliet quickly, according to the custom of the Church, because if they do not, they will offend God even further. Of course, the Friar is eager for the funeral to take place quickly, because it is key to his plot to reunite Juliet, who is only temporarily "dead," with Romeo.
The next quote is in the final scene of the play. It is from the Friar again, and this time he is speaking to Juliet, who is awakening from her drug-induced slumber to find Romeo, who believed that she was truly dead, lying dead beside her. The Friar tells her that "A greater power than we can contradict / Hath thwarted our intents." By this he means that, despite their efforts to reunite Romeo and Juliet, fate, which is a "greater power that we can contradict," has kept them from succeeding. The Friar recognizes with this line what the audience has known since the beginning of the play—that Romeo and Juliet are "star-cross'd," meaning that their love was doomed from the start, and all of their actions, as well as those of the Friar, could not change their fate.