28The rest of the people, the priests, the Levites, the gatekeepers, the singers, the temple servants, and all who have separated themselves from the peoples of the lands to the Law of God, their wives, their sons, their daughters, all who have knowledge and understanding, 29join with their brothers, their nobles, and enter into a curse and an oath to walk in God's Law that was given by Moses the servant of God, and to observe and do all the commandments of the LORD our Lord and his rules and his statutes. 30"We will not give our daughters to the peoples of the land or take their daughters for our sons. 31And if the peoples of the land bring in goods or any grain on the Sabbath day to sell, we will not buy from them on the Sabbath or on a holy day. And we will forego the crops of the seventh year and the exaction of every debt.
Our relationship with God is a bit different than the Israelites here, but we're still supposed to be set apart. We don't have Sabbath years of financial Jubilees, but some of the stuff here we can still take to heart.
The one that struck me the most was verse 30; we're not to be wedded to the "peoples of the land." That applies to things more than just marriage; partnering with non-believers is a recipe for trouble as well.
For instance, American evangelicals are struggling to figure out how to work within a broad-based center-right coalition, how to advance the cause of Christ without getting too cozy with the peoples of the land. Critics are quick to point out that secular conservatives have gotten the better of the bargain, as much of their economic and foreign policy agenda has been enacted, but little of the evangelical political agenda has come to pass.
In a largely secular society, it's hard not to be somewhat intertwined with non-believers unless you set up Christian communes. We just need to be careful not to let the interactions compromise our faith and our witness.