All funds received (cash and checks) should be deposited into the bank as soon as possible. If the deposit is made on Monday, it would be best to have the funds counted by least two people and then secured in a safe. The count sheet should be signed by both people and attached with the deposit ticket.
The checkbook for the church could be kept off premises. The internal control to protect the church and the individual would be that the individual with control of the checkbook either not be a check signer or that someone independent of that person receive the bank statements directly from the bank and review the statement and the canceled checks to make sure they are appropriate.