"sound the flute" what imagery does the line us?

Blake begins the seasonal cycle poems in spring, personified as an angelic male figure with “dewy locks,” “angel eyes,” “holy feet,” and “perfumed garments.” The earth is represented as a female, maturing to an age of sexual willingness. The speaker is asking for the male angel spring to come down to earth and prepare to sow the seed of a new cycle. Sound the flute is an evocation of new life and celebration. The imagery od green grass and nature coming alive after the dormancy of winter.