Accounting approaches the world of economic transactions from the viewpoint of Capital Transformation. Accounting books record the source of the Capital and the form it takes after passing through a company's productive & administrative mechanism. Since Accounting wants to capture these two pieces of information (whence the Capital comes - to what it is transformed), it needs two operations - and Accounting has indeed two and two only operations: Credit & Debit. Traditionally we always say "Debit & Credit" and we always put "Debits" to the "left" (of a page) and "Credits" to the "right" (of a page). But causally speaking, the act which the operation "Credit" captures comes first: because Credit shows the source of the Capital, while Debit shows to what the capital has been transformed before. That's why "A Debit must always equal the corresponding Credit".
Suppose now that the company's Board of Directors, after receiving the cash from the shareholders, decides to spend it in order to buy new productive equipment, striking a deal with a supplier to pay him or her after 60 days from purchasing the equipment. In order to reflect this transaction we need to record two different Accounting Entries.
A) The purchasing of the equipment under 60 days credit terms. Here, since we are buying "on credit", the supplier essentially supplies us with Capital (for 60 days). So we will Credit the Suppliers Account in order to show that we initially are buying the equipment using the suppliers capital, and we will Debit a Fixed Assets account (with equal amount) in order to show that we transformed this capital into Equipment.
B) The cash payment for the equipment after 60 days. Here Accounting sees that capital available to us in the form of Cash (the initial shareholders capital increase in cash), is transformed into Capital returned to supplier. So we will Credit our Bank Account (to show whence capital comes), and we will Debit the Suppliers Account to show to what we have transformed this capital (into Capital Returned to the Supplier).