▼6:2Augustine and others say that this passage refers to the lineages of Seth and Cain, the one being holy and close to God, and the other living apart from God. My suggestion is a more generalized version of what Augustine said, namely, that the sons of God are those who stayed close to God in their lives, and the sons of men are those who lived merely secular lives. In the Bible, the term ‘sons of’ does not necessarily connotate lineage. For example, those who commit adultery are called, ‘sons of adulterers,’ not because their parents were also adulterers, but because they act as if they were sons of adultery personified. There were, in ancient times, prior to any organized religion as we have today, some who were holy, who lived close to God, and who, as a result, lived long lives. But these sons of God were attracted to women who were not holy, who lived secular lives. Thus God generally limits the length of our lives because of sin.(Conte)

▼6:2 The sons of God: The descendants of Seth and Enos are here called sons of God from their religion and piety: whereas the ungodly race of Cain, who by their carnal affections lay grovelling upon the earth, are called the children of men. The unhappy consequence of the former marrying with the latter, ought to be a warning to Christians to be very circumspect in their marriages; and not to suffer themselves to be determined in their choice by their carnal passion, to the prejudice of virtue or religion.(Challoner)