‘The Child is father of the Man’ is a line from Wordsworth’s-

It’s from the poem ‘My Heart Leaps Up’, also known as 'The Rainbow', by the British Romantic poet William Wordsworth.’My heart leaps up when I beholdA rainbow in the sky:So was it when my life began;So is it now I am a man;So be it when I shall grow old,Or let me die!The Child is father of the Man;And I could wish my days to beBound each to each by natural piety.’