What have historically been three main threats to the productive work and growth of a church? First, would be doctrinal issues. If a church is not understanding and practicing sound doctrine then that puts the church at risk of not being in Christ (as warned against in Revelation 2 and 3). Second, is harmony amongst brethren within a local work. There are many warnings throughout the New Testament epistles to churches encouraging everyone to get along. The third threat to a church is sexual impurity; especially amongst the leadership of the church. Though all three are crucial to guard against; perhaps the most neglected of the three is the third one.
A church will be damaged by any sexual impropriety within its members, but when a preacher or elder is involved it can severely damage and/or cripple a work. Oftentimes for years, other times for generations, and sometimes permanently. I’m not sure we as brethren are always cognizant of just how big a threat it is and how much the New Testament warns against sexual impurity. Consider the following passages.
Act 15:20 - “but that we write to them to abstain from things polluted by idols, from sexual immorality, from things strangled, and from blood.”
Romans 13:9 - “For the commandments, "YOU SHALL NOT COMMIT ADULTERY," ... "YOU SHALL NOT COVET," and if there is any other commandment, are all summed up in this saying, namely, "YOU SHALL LOVE YOUR NEIGHBOR AS YOURSELF."
1 Corinthians 5:9 - “I wrote to you in my epistle not to keep company with sexually immoral people. Yet I certainly did not mean with the sexually immoral people of this world,... since then you would need to go out of the world. But now I have written to you not to keep company with anyone named a brother, who is sexually immoral... not even to eat with such a person.”
2 Corinthians 12:21 - “lest, when I come again, my God will humble me among you, and I shall mourn for many who have sinned before and have not repented of the uncleanness, fornication, and lewdness which they have practiced.”
Galatians - 5:19-21 - “Now the works of the flesh are evident, which are: adultery, fornication, uncleanness, lewdness,... those who practice such things will not inherit the kingdom of God.”
Ephesians 5:5-7 - “For this you know, that no fornicator, unclean person, nor covetous man, who is an idolater, has any inheritance in the kingdom of Christ and God.... for because of these things the wrath of God comes upon the sons of disobedience. Therefore do not be partakers with them.”
Philippians 4:8 - “Finally, brethren, whatever things are true, whatever things are noble, whatever things are just, whatever things are pure, whatever things are lovely, whatever things are of good report, if there is any virtue and if there is anything praiseworthy—meditate on these things.”
Colossians 3:5-6 - “Therefore put to death your members which are on the earth: fornication, uncleanness, passion, evil desire, and covetousness, ... Because of these things the wrath of God is coming upon the sons of disobedience,”
1 Thessalonians - 4:3-5 - “For this is the will of God, your sanctification: that you should abstain from sexual immorality; that each of you should know how to possess his own vessel in sanctification and honor, not in passion of lust,..”