Why did U.S. and Filipino forces retreat to the Bataan Peninsula?

Following the Japanese invasion of the Philippines in December 1941, U.S. and Filipino forces retreated to the Bataan Peninsula to execute a planned final stand.12

General Douglas MacArthur ordered this withdrawal to the jungle redoubt of the peninsula to deny the Japanese military the use of Manila Bay. Manila, located on the bay, was a vital deepwater port that the Japanese sought to secure as a primary resupply point for their broader campaign to conquer the southern Pacific. By holding the peninsula and the nearby Corregidor Island, Allied forces aimed to block Japanese access to this strategic harbor.231