“If Jesus is precious to you, you will not be able to keep your good news to yourself. You will be whispering it into your child’s ear. You will be telling it to your husband. You will be earnestly imparting it to your friend. Without the charms of eloquence you will be more than eloquent: your heart will speak, and your eyes will flash as you talk of His sweet love.
Every Christian here is either a missionary or an impostor. Recollect that. You either try to spread abroad the kingdom of Christ, or else you do not love Him at all. It cannot be that there is a high appreciation of Jesus and a totally silent tongue about Him. Of course I do not mean by that, that those who use the pen are silent: they are not. And those who help others to use the tongue, or spread that which others have written, are doing their part well: but that man who says, ‘I believe in Jesus,’ but does not think enough of Jesus ever to tell another about Him, by mouth, or pen, or tract, is an impostor.
You are either doing good, or you are not good yourself. If thou knowest Christ, thou art as one that has found honey. Thou wilt call others to taste of it. Thou art like the lepers who found the food which the Syrians had cast away: thou wilt go to Samaria and tell the hungry crowd that thou hast found Jesus, and art anxious that they should find Him too. Be wise in your generation, and speak of Him in fitting ways and at fitting times, and so in every place proclaim the fact that Jesus is most precious to your soul.”
–Charles H. Spurgeon, “A Sermon and a Reminiscence,” Sword and the Trowel (March 1873), as cited on http://www.spurgeon.org/s_and_t/srmn1873.htm.