In Accounting, everything must balance. Each entry posted to a manual ledger or a complicated accounting system must balance. Debits always equal Credits. This means that like yin/yang, up/down, in/out, there must be two components to an entry. Let me try to explain with an example: I buy office supplies for cash, so the entry will be an increase in office supplies (debit) and a decrease in cash (credit).
No matter how complicated the entry is, it must always balance!ย