Charles Ellicott Commentary 1 Samuel 1:11

"And she vowed a vow, and said, O Jehovah of hosts, if thou wilt indeed look on the affliction of thy handmaid, and remember me, and not forget thy handmaid, but wilt give unto thy handmaid a man-child, then I will give him unto Jehovah all the days of his life, and there shall no razor come upon his head." — 1 Samuel 1:11 (ASV)

And she vowed a vow. — Hannah's vow contained two solemn promises. The first pledged the son she prayed for to the service of the Eternal all the days of his life. The mother looked forward to a lifelong service in the ritual of the Tabernacle for him, but the Being who heard her prayer destined her son for higher work. In his case, the priestly duties were soon merged with the far more responsible ones of the prophet—the great reformer of the people. The second promise was that he would be a Nazarite. Now, Nazariteship included three things: refraining from intoxicating drinks, letting the hair grow, and avoiding all ceremonial defilement by corpses, even of the nearest kin. Samuel was what the Talmud calls a perpetual Nazarite.

These strange restrictions and customs had an inner meaning:

• The abstinence from wine and strong drink symbolized the Nazarite's determination to avoid all sensual indulgence that might cloud the mind and make a person unfit for prayer to, and work for, the Lord.
• Avoiding contact with the dead was a perpetual outward protest that the one who made the solemn vow renounced all moral defilement and gave up everything that could stain and soil a life consecrated to the Eternal’s service.
• The untouched hair, which is especially mentioned here, was a public protest that the consecrated one had determined to refrain from engagement with the world and to devote the whole strength and fullness of life to the Lord’s work.

The Septuagint (Greek) Version here inserts the words, and he shall drink neither wine nor strong drink, wishing to bring the passage into stricter accordance with Numbers 6:0. The original Hebrew text, however, contents itself with merely specifying the outward sign of the untouched hair, by which these solemnly consecrated individuals were publicly known.