"The sons of God saw that the daughters of men were beautiful; and they took wives for themselves, whomever they chose" (NASB). It is not entirely obvious who the parties ("sons of God" and "daughters of men") to the historical event (or rather historical crime, cf. Gen. 6.3) thus described in Gen. 6.2 actually were. Calvin identifies several possibilities. Some -- namely, persons "fascinated by ravings... gross and prodigious" -- have thought the "sons of God" to be angels, who in defiance of divine design engaged in "intercourse with [human] women." Calvin rejects this interpretation on the grounds of "its own absurdity." Angels, by common theological consent, are by their very nature spiritual beings that lack the corporeal presence and procreative impulse necessary to marriage and intercourse (cf. Matt. 22.30).
Calvin is equally dismissive of a second interpretive option which identifies the "sons of God" as nobility who violated proper social hierarchy by marrying "the daughters of plebeians." This view he merely labels "frigid." Gen. 6 is not, in his judgment, included in Scripture for the purposes of reinforcing any given caste system.
Calvin adopts the view that "sons of God" is here a reference to the descendants of Seth, among whom "the pure and lawful worship of God" had thus far prevailed, while "daughters of men" refers to "the children of Cain." In part he adopts this perspective by a process of elimination: when in doubt, choose the interpretive option that doesn't entail ascribing corporeality and corporeal functions to angelic creatures or serve to absolutize a social construct like the relations of nobility to peasantry. Calvin's view also, however, has the merit of respecting its context; the chapters leading up to Gen. 6 serve to detail the genealogies and differences of Cain's and Seth's lines respectively. It is, then, most natural to read the reference to "sons of God" in Gen. 6.2 as a further reference to Seth's line, which has already been identified as proper worshipers of the true God, and so to see Gen. 6 as advancing the great drama of that conflict between the respective seeds of the woman and the serpent -- a conflict which will reach its apex in Christ's life, death, and resurrection.
Calvin's interpretation has the further benefit of yielding both a significant theological truth as well as a very concrete and practical exhortation regarding how Christian believers should approach the task of finding a spouse. The theological point really stems from a potential problem with Calvin's interpretation, the fact that his reading has "sons of God," persons ostensibly characterized by sanctity, committing an act which effectively proves them to be decidedly un-sanctified.
Calvin sidesteps this problem rather easily by observing that these guilty "sons of God" were designated so by virtue of their "external vocation" and outward participation in the people of God, not by virtue of that "eternal election" which properly defines a person as an adopted child of the Eternal King. These men were, in other words, "wolves... within the fold;" members of the visible Church who were not invisibly joined to Christ. Thus Calvin finds in Gen. 6.1-3 the first biblical reference to the distinction between that broad circle of those who belong to the covenant and participate in the rituals and external blessings of the same and that narrower circle of those within the covenant who, properly elected by God, enjoy the spiritual reality (salvation through union with Christ) which all the rituals and external blessings point towards. Gen. 6.1-3, in other words, introduces a categorical distinction within God's people which will persist until the final judgment (the over-realized eschatological objections of our Baptist friends, who wish to discover a covenant and covenant sign which pertains only to indubitably true believers, notwithstanding).
The practical exhortation Calvin discovers in these verses stems from careful consideration of the crime which the "sons of God" here committed. "It is not fornication [or some other sexual sin] which is here condemned in the sons of the saints, but... too great indulgence of license in choosing themselves wives." These nominally Christian men sinned, in short, by marrying the wrong women, not because the women in question were committed to other men, but because they lacked that saving faith in God which renders a potential spouse appropriate to a believer.
The moral implication for single believers today is, I suppose, rather obvious; but before we let Calvin make the point explicit, it's worth noting several things for which Calvin doesn't incriminate these "sons of God." First, he doesn't incriminate them for marrying per se. Marriage as such is an honorable institution (cf. Gen. 2.21-24), and there's nothing in Gen. 6 or in Calvin's reading of it to indicate that fault should be found with these "sons of God" for preferring the married to the celibate life.
Secondly, Calvin doesn't incriminate these men for exercising the faculty of choice in marrying. Individuals should, Calvin seems to assume, have the principal say in who they wish to marry (within those boundaries established by God). The fault of these persons did not lay in any failure to honor someone else's conviction about who their spouses should be. Calvin at least allows, if he does not implicitly encourage, the view which Martin Luther made explicit: that -- all things being equal (i.e., all potential spouses being godly) -- marriages should be contracted on the basis of love and the free decision of the parties involved, and that no one (particularly parents) should interfere in such arrangements without good cause.
Thirdly, Calvin doesn't incriminate these men for choosing beautiful wives: "Moses does not deem it worthy of condemnation that regard was had to beauty in the choice of wives." Physical attraction to a potential spouse is not only lawful but desirable. Physical attraction can, however, turn problematic; in Calvin's judgment the unlawful decision on the part of the "sons of God" to marry beautiful but unbelieving women stemmed from unbridled lust for them. "Our appetite becomes brutal, when we are so ravished with the charms of beauty, that those things which are chief [i.e., godliness in a potential spouse] are not taken into the account."
All of this, of course, contains fairly obvious moral implications for believers in every subsequent age. "We are taught... in these words, that temperance is to be used in holy wedlock, and that its profanation is no light crime before God." The profanation of holy wedlock consists in the sin -- and it is, for Calvin, very clearly a sin -- of marrying someone who does not belong to the people of God. It is a sin that will, Calvin thinks, inevitably lead to more sin and ultimately even apostasy: "It is impossible but that, in the succession of time, the sons of God should degenerate, when they thus bound themselves in the same yoke with unbelievers."
Step number one for choosing a spouse, then, is this: choose a believer. Calvin's rather black and white moral exhortation, and the rather overt assumption underlying it (that single Christians are not in fact free to marry absolutely anyone they might wish), will undoubtedly prove jarring (even to some Christians) in our present day culture, which is squeamish about moral absolutes pertaining to relationships and seems particularly hell-bent on stripping away restrictions on who individuals can lawfully set their affections upon. C'est la vie, as Calvin never said. The good news for single Christians is that Calvin has no problem with you pursuing, with the intent to marry, a believing person of the opposite sex because you think that person's smoking hot (among other virtuous qualities, of course).
Aaron Clay Denlinger is professor of church history and historical theology at Reformation Bible College in Sanford, FL.