THE newly established Christian congregation would have an important role in the fulfillment of Jehovah’s purpose. But the first-century Christians quickly came under attack. Would they keep their integrity to God in the face of persecution from without and other more subtle dangers from within? The Christian Greek Scriptures contain 21 letters that offered needed counsel and encouragement.

Fourteen of the letters​—from Romans to Hebrews—​were penned by the apostle Paul. These letters are named after those to whom they are addressed​—whether an individual or the members of a particular congregation. Consider some of the subjects covered in Paul’s letters.

Admonition on morals and conduct. Those who practice fornication, adultery, and other gross sins “will not inherit God’s kingdom.” (Galatians 5:19-21; 1 Corinthians 6:9-11) Worshippers of God must be united regardless of nationality. (Romans 2:11; Ephesians 4:1-6) They should cheerfully give of themselves to help fellow believers in need. (2 Corinthians 9:7) “Pray incessantly,” Paul says. Indeed, worshippers are encouraged to pour out their hearts to Jehovah in prayer. (1 Thessalonians 5:17; 2 Thessalonians 3:1; Philippians 4:6, 7) For prayers to be heard by God, they must be offered in faith.​—Hebrews 11:6.

What will help families to thrive? Husbands should love their wives as their own bodies. Wives should have deep respect for their husbands. Children should obey their parents, for this is pleasing to God. Parents need to guide and train their children lovingly, using godly principles.​—Ephesians 5:22–6:4; Colossians 3:18-21.

Light shed on God’s purpose. Many aspects of the Mosaic Law served to safeguard and guide the Israelites until the arrival of Christ. (Galatians 3:24) Christians, however, do not need to observe that Law in order to worship God. In writing to the Hebrews​—Christians of Jewish background—​Paul shed much light on the meaning of the Law and on how God’s purpose is fulfilled in Christ. Paul explained that various arrangements under that Law had prophetic value. For example, the sacrificing of animals foreshadowed Jesus’ sacrificial death, which would accomplish true forgiveness of sins. (Hebrews 10:1-4) By means of the death of Jesus, God canceled that Law covenant, for it was no longer needed.​—Colossians 2:13-17; Hebrews 8:13.

Direction on proper congregation organization. Men willing to handle responsibilities in the congregation must have high moral standards and meet spiritual qualifications. (1 Timothy 3:1-10, 12, 13; Titus 1:5-9) Worshippers of Jehovah God should regularly gather with fellow believers to encourage one another. (Hebrews 10:24, 25) Meetings for worship should be upbuilding and instructive.​—1 Corinthians 14:26, 31.

By the time Paul wrote the second of his two letters to Timothy, the apostle was back in Rome; he was imprisoned, awaiting judgment. Only a courageous few risked visiting him. Paul knew that his time was short. “I have fought the fine fight,” he said. “I have run the course to the finish, I have observed the faith.” (2 Timothy 4:7) Likely Paul suffered martyrdom shortly thereafter. But the apostle’s letters guide true worshippers of God to this day.

​—Based on Romans; 1 Corinthians; 2 Corinthians; Galatians; Ephesians; Philippians; Colossians; 1 Thessalonians; 2 Thessalonians; 1 Timothy; 2 Timothy; Titus; Philemon; Hebrews.