Our grandson Jackson's thrilled response to his grandmother's gift of the red pen led to his desire to share the story of his good fortune. "I've got to tell!" he said with all the enthusiasm of someone who knows that a treasure has just been found and obtained.
The born again believer will experience the same longing to share our blessedness as we consistently walk with the God who "out of His infinite riches in Jesus, giveth and giveth and giveth again." The Christian life begins with the living Word of God inhabiting our very being. By definition, such a One indwelling our spirits will move upon us and within us to bear witness of such goodness. This is the reason the Apostle Paul declared our words to be a factor in salvation.
"If thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart God hath raised Him from the dead, thou shalt be saved. For with the heart man believeth unto righteousness, and with the mouth confession is made unto salvation" (Romans 10:9-10).
Paul knew that a true experience of Christ would lead to genuine desire to give to others what we ourselves have been given. Our testimony is the means by which we share the gift, and it is impossible that the love of Christ can authentically be received without it also birthing the "I've got to tell" desire expressed by Jackson concerning his red pen. The issue is not so much a matter of responsibility as it is of a can't help it passion experienced by all who are the beneficiaries of "so great salvation." Indeed, to the degree we are walking in the grace and truth of the Lord Jesus will be the degree to which His "burning and shining light" inevitably motivates us to glimmer forth with the testimony of God's goodness to us (Hebrews 2:3; John 5:35).
I grew up in a spiritual tradition that emphasizes witness more as a matter of obligation than the abundant overflow of a grateful heart and a subsequently motivated tongue (an emphasis that was rarely successful in fostering witness in most believers). Certainly there is truth in the notion of responsibility to tell. However, the dynamic of grace and truth in the Lord Jesus as taught in the New Testament emphasizes that our faithfulness is always fruit rather than root. "As ye have therefore received Christ Jesus the Lord, so walk ye in Him." Reception first, then the subsequent walk of faith and obedience - this is the dynamic that originated our relationship with God, and the dynamic by which it must continue. The mechanism of grace and truth includes our witness, and our mouths will bear genuine and effective witness only as Christ is known as the abundance of our hearts (Colossians 2:6; Matthew 12:34).
The Christian life involves an ongoing reception of "life and breath and all things." Just as importantly, it is meant to be a conscious experience of "the unsearchable riches of Christ." To the degree that it is will be the degree to which the "I've got to tell" empowers and motivates our tongues. We all have different lives and callings, of course, and our Lord will lead us accordingly. We therefore do well to ask Him for many opportunities to "tell the old, old story of Jesus and His love." And we do even better to ask Him for the living experience of Christ whereby our words are weighted with His love received in us, and then inevitably declared by us (Acts 17:25; Ephesians 3:8).
"Ye shall receive power, after that the Holy Spirit is come upon you: and ye shall be witnesses unto Me."