No, 'tis you would be harping upon that string, sir: see you this?
"I can't fathom his motive, Tom," said Richard, harping upon the theme.
Latterly she had been for ever harping upon this one theme,––her duty!
What, is the use of harping upon this subject Sunday after Sunday?
This may be attributed partly to the harping upon a conviction of sinfulness, which in itself is wholly of an unhealthy character.
It was not satisfactory to my lady, and she kept Lucy the whole of the morning, harping upon the sore point.
Every group and person vested with authority strengthens possessed power by harping upon the sacredness of immutable principle.
I strike this note again and again, insisting upon it, harping upon it; for it is the key-note of the music.
He goes on harping upon the Archduchess Elizabeth, and worrying poor Leopold to resume negotiations.