Charles Ellicott Commentary Judges 13:5

"for, lo, thou shalt conceive, and bear a son; and no razor shall come upon his head; for the child shall be a Nazirite unto God from the womb: and he shall begin to save Israel out of the hand of the Philistines." — Judges 13:5 (ASV)

No razor shall come on his head. —The law of the Nazarite is set forth in Numbers 6, and when that chapter is read as the Parashah (or first lesson) in the synagogue worship, this account of the birth of Samson, the first recorded Nazarite, is read as the Haphtarah (or second lesson).

Shall begin to deliver. —The weaknesses of Samson’s own character rendered him unfit to achieve that complete deliverance which was carried out by Samuel. In the cases of Jephthah and Samson, the Israelites learned the power which rests in individual vows to display the hidden and mysterious heroism of the human spirit, and to save people from sinking into the lowest depths (Ewald, 2:397). The vow became a new force of the age. In Jephthah’s case it had been an isolated vow, but in Samson’s it was the devotion of a life, and developed an indomitable energy and power.