Bede : However, the Philistine came forward morning and evening, etc. The number of forty days, during which the Philistine came forward and stood against Israel, represents all the time of the Church, during which it struggles in this life and, with the aid of the grace of the Gospel, tries to fulfill the Decalogue of the law amid the snares of the ancient enemy. Every day, he comes forward to tempt, morning and evening; for he tries to corrupt either the beginnings or the end of all our works of light. He terrifies the weak morning and evening, whom he struggles to overpower either by adversities or by prosperities; the same time of the struggling Church is specifically expressed in its head, when He was in the desert for forty days and was tempted by Satan. But the cunning tempter, who long rejoiced in having conquered the first Adam, perpetually grieves in being defeated by the second. — Commentary on Samuel