In "The Wizard of Oz" the Tin Man's journey led him to finding a heart. The Lion's journey found him courage. The Scarecrow's journey granted him smarts. Dorothy's adventure resulted in observing all these and that Love binds them all which for her was found at home.
In a similar way, the Christian's journey must take a path that develops one's integrity. The heart, courage (especially to witness), knowledge, and love that a Believer in Christ matures in is crucial for personal growth and a healthy appreciation of our true Home - New Jerusalem and New Earth.
Scripture deals with each one of these areas. Proverbs 4:23 mentions the importance of the heart - Above all else, guard your heart, for it is the wellspring of life. Wellspring in the original Hebrew, tôtsâ'âh tôtsâ'âh
(to-tsaw-aw', to-tsaw-aw') means the outgoing issues. So, whatever issues you hold dear in your heart, guard those because they will find their way out to aid you in life.
Courage, especially in witnessing, can be silent, but with time running out fast speaking up and out by the Christian is desperately needed. The tongue or words we choose to say should be extremely pre-considered and screened through the Holy Spirit. I am so guilty of Not following through on both accounts in many of my daily interactions. Here is just a taste of what the Holy Spirit says through James - The tongue also is a fire, a world of evil among the parts of the body. It corrupts the whole person, sets the whole course of his life on fire, and is itself set on fire by hell. All kinds of animals, birds, reptiles and creatures of the sea are being tamed and have been tamed by man, but no man can tame the tongue. It is a restless evil, full of deadly poison. (James 3:6-8) When the moments to say what YOU really want to say come - STOP, ask the Holy Spirit what would make Him proud of you to say and for the words, then speak.
"Knowledge is power" (attributed to Sir Francis Bacon) is a true statement. Do you want to be able to test and approve what God's good, pleasing and perfect will is? Then shed or metamorphize from your highly world-influenced self into a Christ-minded/centered person by performing some serious mental and spiritual renovation. That was my paraphrase of Romans 12:2. Here is the actual verse - Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is--his good, pleasing and perfect will. The key here is to renovate your mind. Do some spring cleaning with the Holy Spirit about your thought life, identify what should not be there any more and replace it with what should.
Knowledge is power, but it is not everything. Courage to speak and act is extremely helpful, but it is not the all-in-all of a Christian's development. You could make a case for the Heart, especially with the words "Above all else" in front of it being everything. However, wherever you place Love, in the mind or heart or wherever - Love is everything. "If I speak in the tongues of men and of angels, but have not love, I am only a resounding gong or a clanging cymbal. If I have the gift of prophecy and can fathom all mysteries and all knowledge, and if I have a faith that can move mountains, but have not love, I am nothing. If I give all I possess to the poor and surrender my body to the flames, but have not love, I gain nothing. ...13 And now these three remain: faith, hope and love. But the greatest of these is love." (1 Corinthians 13:1-3; 13) I believe we see everything, including Love, very poorly right now because of our fallen state. "Now we see but a poor reflection as in a mirror;then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known." (1 Corinthians 13:12) This makes me look forward to what Love will be like in the New Heaven and New Earth but makes me want to meet the need for Love more now than ever before.
So, your heart should be guarded and set apart for Christ. Your speech should be guarded and set apart for Christ. Your mind should be guarded, transformed, renovated and set apart for Christ. And your Love for God and others should be active with the excitement that your efforts will see you mature into a man or woman in Christ who is filled with integrity.