Profit and loss
Is about revenue and expense. E.g. sales, license fees, bills, etc.
Balanced sheet
is about asset and liability
E.g. Assets can cash, house, equipments, etc.
liability can a loan
The difference between asset and liability is the equity, i.e. how much the company worth at some point in time
As a company buying equipment, selling products, paying bills, etc. the profit and loss accumulated for a period of time, e.g. a month, should match the balanced sheet change for that month.
Profit and loss indicates how well the company is running for a period of time.
Balanced sheet indicates the financial position at a point in time.
Some accounting practices.
Accrue an expense (monthly estimated bill) and reverse it later when the actual expense bill is there
Prepayment for e.g. software license, to smooth the expense over time
Purchase order, without the GL account, because don't know the supplier yet.