Final answer:
The lines that indicate morning are from Shakespeare's 'Romeo and Juliet' and describe the dawn in poetic terms. Juliet claims the bird song is a nightingale to prolong Romeo's stay, as nightingales signify night. The nightingale's song in literature often symbolizes love and sacrifice.
Step-by-step explanation:
The lines that indicate it is morning are from William Shakespeare's Romeo and Juliet, where the text reads, "Look, the morn, in russet mantle clad, Walks o'er the dew of yon high eastern hill." This visually rich language suggests the arrival of dawn as the morning is personified. Juliet argues that the birdsong is a nightingale's and not a lark's to convince Romeo to stay longer, as a nightingale's song is associated with night, allowing them to ignore the approaching day for a moment longer.
Similarly, various texts presented reflect upon the symbolism of the nightingale's song. For instance, the nightingale's willingness to press against a thorn for the sake of love, as depicted in the passage: "And when the Moon shone in the heavens the Nightingale flew to the Rose-tree, and set her breast against the thorn. All night long she sang with her breast against the thorn, and the cold crystal Moon leaned down and listened." The nightingale's song represents enduring love, sacrifice, and the ethereal nature of true passion.