Treasury of Scripture Knowledge
If the first-fruit
It was God's purpose to bring us into being [spiritually] by the message of truth, so that we could become a kind of "firstfruits" of those He created. [Note: "Firstfruits" here suggests either that Christians are the best of all of God's creatures (Num. 18:12), or that they were the first to be converted, with many more to come].
These people are the ones who did not practice sexual immorality with women, for they were virgins [Note: This probably has reference to people who avoided idolatry]. These are people who followed the Lamb wherever He went. They were purchased from among mankind to be the firstfruits [devoted] to God and to the Lamb.
But some of the branches [of a cultivated olive tree] were broken off [i.e., God's rejection of the Jews] and you [Gentiles], representing a wild olive tree [branch], were grafted into it. So then, you [Gentiles] were able to benefit from the roots and sap of the olive tree, along with the Jews.
1 Corinthians 7:14
For the unbelieving husband is set apart [i.e., as an acceptable mate, although not yet saved. See verse 16], through his wife [i.e., her Christian commitment is viewed as having a godly effect on the home], and the unbelieving wife is set apart through the brother [i.e., for the same reason]. Otherwise, your children would be [considered] unclean. [Note: "Unclean" suggests they would be viewed as pagans were it not for one parent being a Christian]. But, as it is, they are set apart as acceptable [i.e., to God, because of the influence of the one Christian parent].