The Luther Rose

or

Martin Luther's Seal

While he was a professor at Wittenberg University, Martin Luther devised this seal which he declared to be a "summary of my theology." 
In a letter written to his friend, Lazarus Spengler, town clerk of Nuremberg, Germany, Luther explained it's rich meaning.

The first must be a cross, black in the heart, so that I remind myself that faith in the Crucified One saves me. For one who believes from the heart will be justified [Rom. 10:10]. Even though it is a black cross and mortifies and hurts, yet it leaves the heart in its natural colour (red). It does not destroy our natural personality. It does not kill, but it rather allows us to live. For the just lives by faith [Hab. 2:4; Rom.1:17; Heb. 10:38]. This heart must be set in the midst of a white, gay rose, in order to show that faith produces happiness, comfort, and peace, and not as the world gives [Jn. 14:27]. For this reason the rose must be white and not red. For white is the colour of the spirits and all angels. This rose is set in the centre of an azure background in order to show that this joy is the beginning of a future heavenly joy. And this background is set in a golden ring in order to show that this blessedness in heaven is everlasting and will never end, and is more precious than all joy and earthly possessions, just as gold is the most precious of all metals.

Thus, the Luther Rose represents the essentials of the Gospel:

The black cross represents the total depravity of man and the tremendous sacrifice Christ made by giving up His life for the ungodly.

The red heart represents the love of God in sending His own Son to give His life for the salvation of the elect. Salvation is all of grace, not of works, in Christ alone.

The white rose represents the sinlessness and joy of Jesus Christ our Savior, and the cleansing and happiness we receive by His justifying grace. Having five petals, it also represents the five great truths of the Protestant Reformation: sinners are saved by Grace Alone (Sola Gratia) through Faith Alone (Sola Fide) in Christ Alone (Solus Christus) on the basis of Scripture Alone (Sola Scriptura) to the Glory of God Alone (Soli Deo Gloria).

The blue background represents the glories of heaven that await those who believe by faith alone in the sovereign King of kings and Lord of lords, Jesus Christ.

The gold ring which surrounds the blue background represents the most precious treasure in all the universe: eternal life and blessedness in Jesus Christ.