A zealous person is contagious, both positively and negatively. The apostle Paul cautioned that the early believers had been zealously affected, but not in a good way. Those who opposed the gospel were adamant, yet they unwisely waged war against the truth. Night and day, they zealously fought in order to hinder the ministry of the believers. Ultimately, their zeal affected the people of God. These believers who started strong were hindered by the enemies' efforts to the point that it affected their race for the Lord (Galatians 5:7). Modern day enemies of the gospel are aware of this potential pitfall for the believers. They often display more zeal than those who knowingly possess the truth. Yet, today's passage also teaches that “it is good to be zealously affected always in a good thing.” Zeal breeds zeal. Zeal in righteousness will yield righteous results.
Zeal involves a fervent desire to accomplish some particular feat. The Bible tells us that Christ died on the cross to redeem a people who would then become zealous of good works. Every Christian should strive to be zealous in his service to the Lord. Many believers during periods of great persecution zealously gave their lives for the gospel’s sake. Acts 15:26 tells of men who “hazarded their lives for the name of our Lord Jesus Christ.” These people recognized that they were no longer their own but God’s. They had been redeemed by the precious blood of the Lord Jesus Christ and willingly sealed that testimony with their own blood. The more the enemies of God persecuted them, the more freely the gospel spread.