I want you to be wise in what is good and innocent in what is evil (Romans 16:19).

In Paul's final instructions to the Roman Christians, he warns them against false teaching and commends their reputation of obedience. Then he asserts a principle that should guide all their behavior, namely, that they should be wise in what is good and innocent in what is evil. 

Let's unpack this.

Wisdom is built on prior knowledge and understanding that is honed by deliberate practice over time. One dictionary definition of wisdom is "the ability to discern or judge what is true, right, or lasting." Wisdom in the moral and spiritual realm, therefore, suggests maturity:

But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil (Hebrews 5:13).

Therefore, I take biblical wisdom to involve deliberate and focused practice in knowing and applying God's Word over time.

But how about the second part of Paul's instruction: "Be innocent in what is evil"? 

Innocence is not the opposite of wisdom. Foolishness and ignorance would be the opposite of wisdom, but innocence suggests blamelessness and purity, a freedom from any guilt. Therefore, it is not right to take Paul's instruction as a mandate to keep ourselves ignorant of evil. After all, Paul elsewhere based his instructions on their awareness of Satan's schemes (cf. 2 Corinthians 2:11). Innocence, therefore, does not suggest lack of awareness of evil or the evil one.

But here's where a distinction needs to be made. Whille innocence does not require ignorance of evil, it does necessitate inexperience with evil. Knowing about evil does not remove innocence, but practicing evil does.

But can one really know what evil is without actually experiencing it first hand? This sort of logic has led many not only to lose their innocence but also to be entrapped by sin. This sort of logic has led many parents to throw their innocent children into the wilds of public school, where they can "experience" the evils of "peer pressure," "drugs and alocohol," "immorality" and all manner of other sinful behavior. They think that doing this will make their children wise. But throwing simple-minded kids into a sin-infested environment does not hone wisdom, but it does entrench folly. 

No one would accuse the Lord Jesus of being ignorant of evil, yet He was innocent of evil (cf. John 8:46; 2 Corinthians 5:21; Hebrews 4:15). Therefore, we can know what is wrong without ever practicing it ourselves. 

Now, you might ask, how do we know evil without experiencing evil? Consider this. We know murder is wrong without ever seeing it first hand. We know adultery is wrong without ever experiencing the pain and anger it causes. We know evil as evil from the Word of God. God's Word puts every moral act in its proper context. We do not need to put ourselves or our children into the context of "real-world" experience for us to understand evil, for often the world presents many evils in a more acceptable light, so that rather than moral clarity, we only get moral confusion. 

Therefore, I take Paul's call to innocence to involve knowing evil from a biblical perspective so that we avoid it in every way. 

Friends, and especially parents among you, I encourage you to be wise in what is good, that is, take deliberate steps to learn and apply the Word of God and teach your children to learn and apply the moral and spiritual truths of God's Word to their lives. I encourage you also to know what is evil from a biblical perspective so that you will always practice what is good and train your children to do the same. 

Romans 14
1 As for the one who is weak in faith, welcome him, but not to quarrel over opinions.

Another way this has made sense to me is to say don't quarrel over styles and preferences. I think even what is right and acceptable is often quarreled over needlessly. "Should we give the homeless man $100 or $35?" why argue over this? Give! Encourage for maturity but don't needlessly dwell on the good “A” or good “B”.

Teach, encourage, and edify, but we should be cautious not to divide over good and 'gooder.' Leave this division for evils.

Romans 14-15 specifically address the issue that is prominent throughout the Book of Acts, namely, the transitional struggle between the Jewish and Gentile believers. Here "the one whose faith is weak" (Romans 14:1; 15:1) refers to the Jewish believer (e.g. the Gentile believers have no food restrictions as the Jewish believers think they have - see Romans 14:3). The Jew must not judge the Gentile, but at the same time, the Gentile should not look down on the Jew (Romans 14:3). The overriding message is "mutual edification" (Romans 14:19; 15:2). There are more important matters to focus on than these ritual distinctions (Romans 14:17). What is more, even though the Gentile believers are right in what they believe, it would be wrong for them to flaunt this freedom in such a way that Jewish believers are caused to stumble, wheteher by causing them to violate their conscience or leave the fellowship (cf. Romans 14:20-21). 

The primary audience of Romans 14-15 is Gentiles, although there are probably some Jews among them. In chapter 15, the Gentiles are the ones directly addressed with respect to bearing "with the failings of the weak." They are encouraged to be patient with the Jewish believers and accomodate them rather than "to please themselves" (Romans 15:1-2). When Paul cites the Scriptures, the ones directed to the Gentiles vs. the Jews are 3 to 1 (Romans 15:9-12). In Romans 15:14-22 Paul reaffirms his apostleship to the Gentiles, which God has confirmed through the working of signs and wonders through the power of the Holy Spirit (Romans 15:19). This punctuates his instructions with his apostolic authority.

Paul talks about stronger Christians bearing the failing of new or 'weak' Christians. Paul wrote earlier about Jewish converts hanging onto certain teachings from the Mosaic Law - in the manner of food and what day Sabbath is practiced, etc.

(Romans 15:1-2, 5-7)

1 We who are strong ought to bear with the failings of the weak and not to please ourselves. 2 Each of us should please our neighbors for their good, to build them up.

5 May the God who gives endurance and encouragement give you the same attitude of mind toward each other that Christ Jesus had, 6 so that with one mind and one voice you may glorify the God and Father of our Lord Jesus Christ.

7 Accept one another, then, just as Christ accepted you, in order to bring praise to God. 8 For I tell you that Christ has become a servant of the Jews on behalf of God’s truth, so that the promises made to the patriarchs might be confirmed 9 and, moreover, that the Gentiles might glorify God for his mercy

Paul preaches on the importance of unity through forgiveness and carrying each other burdens. Unity of all believers (new and old) was Pauls message that they may worship with one voice and bring maximum glory to God. Unity is a common message we discuss at our church, because disunity can tear apart the church and push new believers away from church. Unity starts with mature believers shedding our rights, that we avoid unnecessary conflict that can harm the larger body. Having been part of our church for several years now I realize now that disunity is a constant enemy that lurks around - it starts often with disagreement and pride, complaints and gossip, hurt feelings and a heart of un-forgiveness. We all need to remind ourselves of the great example of grace and humility that was set by our Lord and Savior as he surrendered his rights (on the cross) that all we would all receive forgiveness.