Responsa על שבת 305:10

Q. Before leaving his place in order to participate in congregational services, A gave money to a Gentile and told him to hire workers immediately and build A's house. Is such an act permissible?
A. A Jew is not permitted to tell a Gentile before the Sabbath to work for him on the Sabbath.
SOURCES: Cr. 44; Rashba I, 875.