Rob Peter to pay Paul
Means take from one and give to another but its origin remains a mystery. The story that funds were taken from the parish of St Peter, Westminster Abbey, to pay for repairs to St Paul’s Cathedral during the 16th century is probably not the source because there is strong evidence the expression was around long before that. The OED gives its origin as late Middle English, which would be around 1450, but some other sources give even earlier dates. Perhaps the expression was inspired by one of St Paul’s letters, II Corinthians, 11: 8, “I robbed other churches, taking wages of them, to do you service” where Paul admits to diverting funds from other churches (perhaps Peter’s?) to help the Corinthians.