Why would firms stop hiring workers when the wage is above the marginal revenue product?

Firms stop hiring workers when wages exceed the marginal revenue product (MRP) because it becomes unprofitable to employ additional workers. The MRP represents the additional revenue generated by hiring one more worker, and if the wage paid is higher than this value, the cost of hiring exceeds the revenue produced. Continuing to hire under these conditions would lead to reduced profits or losses, prompting firms to limit their workforce to optimize costs and maintain profitability.