A student recently sent me a question on 1 John 3:9:
Everyone who has been fathered by God does not practice sin, because God’s seed resides in him, and thus he is not able to sin, because he has been fathered by God. (NET)
This verse has bothered exegetes for a long time because of its absolute stance, which runs contrary to every Christian's experience: We still struggle with sin. Some scholars have argued that the present tense here indicates a continual action ("does not continually practice sin") and as such refers to a believer who habitually and regularly sins without seeking forgiveness from the Father. My students question was essentially whether this view is correct. This classic interpretive question isn't easily answered. Lots of issues come into play, including the force of the present tense, but also the context and historical background of the writing.
As far as the present is concerned, it is somewhat correct to say that the present tense indicates continuous action, but this is a general tendency that admits lots of exceptions. The present tense is a flexible linguistic element, and in certain instances is shows continuous action but in certain contexts it doesn't. I think the key for understanding this passage is to get the entire context of what the author is arguing. Here he is not speaking abstractly, as if "sin" were anything, but concretely in light of the struggles taking place in his churches. On this score I follow the exegesis of one of my mentors, Hall Harris (quotation from his commentary on 1 John, available here):
The unifying theme running through all of 1 John, though, is the absolute necessity to observe the "new" commandment to love one’s fellow member of the community. The genuine Christian cannot and will not fail to do this; a failure to do this demonstrates that one is not a genuine Christian. This is precisely what the author of 1 John wants to say about the secessionist opponents who have denied the apostolic eyewitness testimony about Jesus. By their departure from the community the author is writing to, and their ensuing failure to demonstrate love for those brethren from whom they departed, they have shown that they are not themselves genuine Christians.
So putting the present tense together with this context, I would argue that the translation should be relatively simple: "Everyone born from God does not sin." I would regard the present tense here as indicating a generality, not a continuous action. They key interpretive issue is that John refers to a specific situation: the schism in his church in which a certain group has left the church and thus are not showing love to the brothers. The sin here is thus specific and contextual, not general.
The end result is that John here speaks to a specific, contextual situation, not a believer's struggle with sin generally. Application can readily be made, namely, if we are truly Christians we will maintain fellowship and solidarity with other Christians on key doctrines of our faith.