Because of Accrual Accounting, the Income Statement can lie to you.

Imagine you run an agency. In December, you sign a $50,000 contract, do the work, and send the invoice. On your Income Statement, you record $50,000 in Revenue and show a massive Net Income (Profit). But the client has 90 days to pay you. In January, you have to pay your employees, but you have no actual cash in the bank. You are profitable, but you are broke.