Profit is an accounting position. Cash is a fact. A business can invoice heavily, book a healthy margin, and still be unable to pay salaries at the end of the month — because the profit is sitting in receivables and the salaries are due in cash.
The distance between the two comes down to timing. Revenue is recognised when earned, not when collected. Stock purchased is cash gone but profit unaffected until the item sells. Loan principal repayments never touch the income statement at all, yet they consume cash every month.
The discipline that fixes this is a rolling 13-week cash flow forecast — a week-by-week view of what actually comes in and goes out. It is short enough to be accurate and long enough to give you time to act on what it shows.
If you only ever read one report each month, read the cash flow statement alongside the P&L. Either one on its own will mislead you.