“No soldier on service gets entangled in civilian pursuits, since his aim is to satisfy the one who enlisted him.” 2 Timothy 2:4
No one can serve two masters. Since business affairs often involve the exercise of greed, the faithful churchman must be separate from these.
Ambrosiaster (fl. c. 366-384) from Commentary on the Second Letter to Timothy in the Ancient Christian Commentary on Scripture vol. IX, ed. by Peter Gorday (Downers Grove: IVP, 2000) 240.