From the book, CHRISTIANITY IN TWELVE WORDS, this is from the chapter on “Sound” by Tony Mauck.

Sound is measured by one’s spiritual wellness, period. Sound includes both submissiveness to God in areas of corporate responsibility and submissiveness to God in the area of personal faith and holiness.

Collectively, soundness means…

• Identifying with others who are sound and engaging in God-prescribed acts together.
• Declaring the truth that saves and standing firmly against destructive error.
• Demanding and encouraging a genuine attempt at holiness among all of the members.
• Respecting God’s arrangement for the local church.
• Engaging only in work and worship that is consistent with New Testament instruction.

Individually, soundness means…

• Maintaining a “good and honest heart” (Luke 8:15).
• Paying homage to the great God and Redeemer.
• Trusting Him daily through prayer, study and meditation.
• Serving among His people and expressing genuine concern for each one.
• Pursuing love in all of one’s relationships.
• Imitating the Lord in faith, humility, service and purity.
• Shining as lights in the world in an attempt to reach them with God’s saving message.