European Central Bank
In central banking, the privileged status of the central bank is that it can make as much money as it deems needed. In the United States Federal Reserve Bank, the Federal Reserve buys assets: typically, bonds issued by the Federal government. There is no limit on the bonds that it can buy and one of the tools at its disposal in a financial crisis is to take such extraordinary measures as the purchase of large amounts of assets such as commercial paper. The purpose of such operations is to ensure that adequate liquidity is available for functioning of the financial system.

Q: What is the purpose of buying commercial paper in a time of financial crisis?
to ensure that adequate liquidity is available for functioning