Answer:
When you buy a U.S. government savings bond, you are doing so under the power given to Congress to borrow money on behalf of the United States government. This power is granted to Congress under Article I, Section 8 of the United States Constitution, which gives Congress the power to "borrow Money on the credit of the United States."
The sale of savings bonds is one way that the government can borrow money from individuals and institutions to finance its operations and pay off its debts. When you buy a savings bond, you are essentially lending money to the government, which promises to pay you back with interest at a later date. This allows the government to fund its activities without having to rely solely on taxation and other sources of revenue.
Overall, the sale of savings bonds is just one example of how the U.S. government uses its power to borrow money to finance its operations and fulfill its obligations to its citizens and creditors.