ROMEO Lady, by yonder blessed moon I swear That tips with silver all these fruit-tree tops-- JULIET O, swear not by the moon, the inconstant moon, That monthly changes in her circled orb, Lest that thy love prove likewise variable. ROMEO What shall I swear by? JULIET Do not swear at all; Or, if thou wilt, swear by thy gracious self, Which is the god of my idolatry, And I'll believe thee. ROMEO If my heart's dear love-- JULIET Well, do not swear: although I joy in thee, I have no joy of this contract to-night: It is too rash, too unadvised, too sudden; Too like the lightning, which doth cease to be Ere one can say 'It lightens.' Sweet, good night! This bud of love, by summer's ripening breath, May prove a beauteous flower when next we meet. Good night, good night! as sweet repose and rest Come to thy heart as that within my breast! William Shakespeare, in Romeo and Juliet,Act II, Scene II.