1 Samuel 1:11

She vowed a vow; knowing that her husband would willingly consent to it, otherwise she had not power to do it. If thou wilt indeed look on, to wit, favourably, so as to remove it. The affliction, i.e. the barrenness and reproach which attends it. Give him unto the Lord, i.e. consecrate him to God's service in his temple, as far as in me lies; for if he had any blemish, she might not do it. All the days of his life; not only from his twenty-fifth to his fiftieth year, as all the Levites, and so he himself, were obliged by God, Numbers 4:3, Numbers 8:24, but for his whole time; which is still to be understood with a reservation of God's right, which her now must give place to, as indeed it did; for God called him to be a prophet, and a general of the army, and a judge. There shall no razor come upon his head, i.e. he shall be a perpetual Nazarite; for under this one rule, as the chief, all the rest are contained; as elsewhere the whole Mosaical law is understood, under the title of circumcision.