You should have recorded in your cash books all amounts you've really received and payments you've really made. Though the cash books may be incomplete as your bank may have put extra transactions by your account such as:
? bank fees or interest charges
? direct debits (payments) and direct credits (receipts).
Doing a regular bank reconciliation will permits you to:
? take into account any extra transactions your bank puts by your account and
? check and record any errors or omissions.