The purpose of financial accounting statements is mainly to show the financial position of a business at a particular point in time and to show how that business has performed over a specific period.
The three main financial accounting statements that help achieve this aim are:
(1) The profit and loss account (or income statement) for the reporting period
(2) A balance sheet for the business at the end of the reporting period
(3) A cash flow statement for the reporting period
A balance sheet shows at a particular point in time what resources are owned by a business ("assets") and what it owes to other parties ("liabilities"). It also shows how much has been invested in the business and what the sources of that investment finance were.
It is often helpful to think of a balance sheet as a "snap-shot" of the business - a picture of the financial position of the business at a specific point. Whilst this is a useful picture to have, every time an accounting transaction takes place, the "snap-shot" picture will have changed.
By contrast, the profit and loss account provides a perspective on a longer time-period. If the balance sheet is a "digital snap-shot" of the business, then think of the profit and loss account as the "DVD" of the business' activities. The story of what financial transactions took place in a particular period - and (most importantly) what the overall result of those transactions was.
Not surprisingly, the profit and loss account measures "profit".