"Thy" and "Thee" and "Thou"
Notice how Tagore uses a lot of "thee" and "thy" in "Song VII"? Well, that's a signature of his poetry. Tagore, who translated a lot of his own poetry from Bengali to English, often uses this formal second-person form of address in his poems. We'll find him using this form of address in works like "Closed Path" and "Chain of Pearls", among others.