The question 'How do you know, wife, whether you will save your husband?' (1 Cor 7:16) closes the so called 'Paul's marriage privileges' running in the preceding verses of 1 Cor 7. The issue expressed with a question mark refers to mixed marriages. The present essay aims to explore this already much harvested text from a new exegetical perspective. In the first part, the socio-religious context of the audience in the 1 Corinthians is exposed: the background of their beliefs and dilemmas concerning marriage. In the second part, the issues of the married women position in Judaism and in the Greco-Roman culture of the period are explored. The last step of the investigation is the analysis (mainly rhetorical) of Paul's argumentation in 1 Cor 7:16 in the context of 1 Cor 7:12-16. The final conclusion is that a Christian wife (as well as a Christian husband) cannot save her spouse because, according to Paul's argumentation in the passage, the responsibility for believers' salvation belongs solely to Christ. Nevertheless, a Christian wife can sanctify her husband.