The reason given for this action is that Esau had married a couple of Hittite women who were source of bitterness for Isaac and Rebekah (Genesis 26:34-35).
The charge to not marry a Canaanite seems to speak against marrying across religious lines; but such a conclusion is not indicated by the text. The people of Paddan-aram were not really proper "God" folk. They were polytheists (Genesis 31:19). The real concern, I suspect, was about customs. The customs of the Canaanites was just too drastically different from those of Abraham's family.
There is an application here about where we look for marriage candidates but we must bring in some other scriptures to make the point.
If we look at 2 Corinthians 6:14-15 we read about the problem of being "unequally yoked" with unbelievers.
Do not be mismatched with unbelievers. For what partnership is there between righteousness and lawlessness? Or what fellowship is there between light and darkness? What agreement does Christ have with Beliar? Or what does a believer share with an unbeliever?
This passage is not specifically about marriage but it applies. Murry H. Harris explains that the passage
... clearly is not an injunction against any and all association with unbelievers (cf. 1Co 5:9-10; 10:27). Paul actually encouraged the Christian partner in a mixed marriage to maintain the relationship as long as possible (1Co 7:12-16). Rather, this is a prohibition against forming close attachments with non-Christians, using an agricultural metaphor about yoking (cf. Dt 22:10; also Lev 19:19). Although precisely what constituted a "diverse yoke" for the Corinthians remains unstated, it clearly involved compromise with heathendom, such as contracting mixed marriages (cf. Dt 7:1-3), initiating litigation before unbelievers in cases involving believers (1Co 6:1-8), or forming any relationship with unbelievers that would compromise Christian standards or jeopardize consistency of Christian witness. (Zondervan NIV Bible Commentary: Volume 2, 681)First Peter 3:1-7 is about religiously unequally yoked marriages that have become that way because one of the partners became a believer.
So Paul advises Christians to avoid forming close relationships with unbelievers.
Now, does that mean Baptists should not form close relationships with Methodists? or First Christians shoud avoid romantic relationships with Nazarines? Considering the religious goals of these groups are hopefully similar (they want to go to heaven, they love Jesus, they have a sense of Christian mission and want to grow their faith) we can view people from these various groups on average as religious-culturally similar. Obviously, it is advisable to form close relationships with others who have the most important life goals in common and/or the most compatable as reasonably possible.
And Christians should not eschew the social company of anybody as far as it is possible.
