1 John 3:19 (KJV)  And hereby we know that we are of the truth, and shall assure our hearts before him. 

The Christian life is a conviction of heart and is manifested by outward obedience to the truth of God’s Word. This truth was well spoken by the Apostle John in 1 John 3:16-17 (KJV)  Hereby perceive we the love of God, because he laid down his life for us: and we ought to lay down our lives for the brethren. But whoso hath this world’s good, and seeth his brother have need, and shutteth up his bowels of compassion from him, how dwelleth the love of God in him? 

The test is well attested when the Apostle John observed 1 John 3:18 (KJV)  My little children, let us not love in word, neither in tongue; but in deed and in truth. 

The conscience is said to be God’s spy in our hearts, sent by the Lord, to self-assessment, for His glory – 1 John 3:20 (KJV)  For if our heart condemn us, God is greater than our heart, and knoweth all things. Amen.