When a woman transitions out of marriage due to loss or separation, she assumes total independence over her life and her spoken commitments. A woman who is a widow or a divorcee stands entirely on her own, as she is no longer under the authority of a father or a husband [רש״י, ביאור שטיינזלץ]. Consequently, she bears full responsibility for her words, and any vow she makes is entirely valid and binding upon her [חזקוני]. Because she operates independently, the only method available to dissolve her vows is by consulting a sage [בכור שור].
The primary approach among commentators is that this independence applies specifically to a woman who had entered a full marriage. If a woman is widowed or divorced during the earlier engagement phase, she automatically returns to her father's jurisdiction, and he retains the right to annul her vows [רש״י, רש ר הירש, מלבי״ם]. However, the moment a woman enters a complete marriage, she permanently leaves her father's authority. This holds true even if she is still a young girl [רש ר הירש], or even if the marriage ended while she was in transit from her father's home to her husband's home [תורה תמימה].
On the surface, the binding nature of an independent woman's vows seems entirely obvious. If she has no father or husband to oversee her, there is no one who could possibly cancel her commitments, prompting the question of why this rule needs to be explicitly stated [הכתב והקבלה, תורה תמימה]. The answer lies in how vows are treated in the future. The legal status of a vow is permanently fixed at the exact moment it is spoken. If a widow or divorcee makes a vow, even if she conditions it to take effect only at a later date, a new husband cannot cancel it if she remarries. A husband has no power to annul vows that his wife made before their marriage [הכתב והקבלה, תורה תמימה]. Without this clarification, one might mistakenly assume that just as a husband has certain rights over vows made in her father's house, he could also cancel vows made during her period of independence. The rule emphasizes that commitments from her interim period remain strictly binding and are outside the new husband's control [שפתי חכמים].
The specific placement of this law offers an additional insight, as it appears right before concluding the broader laws of a married woman's vows. This arrangement hints that if the widow or divorcee marries again, her new husband will have the authority to annul any new vows she makes during their marriage. This authority remains intact even if the new marriage violates a religious prohibition, such as a widow marrying a High Priest [מלבי״ם].