Metanoia (right heart), Orthodoxy (right doctrine) and Orthopraxy (right practice)

I think it is far too easy a thing to fall into one of three traps:

1. We can learn all there is to know about Christianity and the Bible, but if our heart does not change, our understanding and knowledge is worthless. 
2. If we allow our heart to be changed so that it is full of love, mercy, and compassion, but somehow fail to live it out in the world, then our faith is fruitless. 
3. If we live out our entire life doing good to everyone we meet, but fail to learn about and align ourselves with the God of the Bible, our good deeds are meaningless. 

According to the New Testament, Christ preached and modeled all three of these.

1. After the Annunciation (announcement of Mary conceiving the Christ-child), Birth of Jesus, Adoration of Jesus by shepherds and wise men, and the Presentation of Jesus at the Temple (required by Jewish Law), Saint Luke tells the story of Jesus at 12 years old, listening, learning, and teaching in the Temple (Luke 2:41-52).  Throughout the New Testament Gospels, Jesus continues to preach in the synagogues, answer questions posed by members of the Sanhedrin (the ruling council in Jerusalem), and answer questions posed by teachers and experts on Scripture.  In several places, Jesus recites Scriptures from memory, and He quotes Scriptures throughout His ministry. Orthodoxy (having the right doctrinal beliefs) was evidently important to Him.
2. As important as right beliefs and right understanding of Scripture were to Jesus, He preached more often on having the right heart (conversion / metanoia).  Saint Matthew quoted Jesus (Matthew 15:1-20) telling His followers how important the heart is.  The heart guides our thoughts, words, and actions.  It is the source of sin.  It is also the source of good.  "The good person acts out of the good treasure of his heart to do what is good, but the evil person acts out of the evil treasure of his heart to do what is evil.  One's mouth speaks from that which fills his heart." (Luke 6:45)  
3. According to Jesus, if one has the right beliefs (orthodoxy) and the right heart (conversion / metanoia), then right action (orthopraxy) should follow.  Indeed, according to Jesus, right action is the indicator of a heart changed by trust in Jesus, which responds in obedience to Jesus' instruction and teaching.  Saint Matthew quoted Jesus saying, "Not everyone who says to me, ‘Lord, Lord!’ will enter the kingdom of heaven, but only those who do what my Father in heaven desires. [...]  everyone who hears these words of mine and does them is like a wise man who built his house upon a rock." (Matthew 7:21, 24)

Without a transformed heart, together with a transformed mind, and a transformed will that does what Jesus said to do and practices what Jesus preached ... we cannot claim to belong to Him.  

 

Jesus reminded His followers to "'Love the Lord your God with all your heart, and with all your soul, and with all your mind.' This is the first and greatest command. And the second is similar, 'You shall love your neighbor as you love yourself.'" (Matthew 22:37-39)

We cannot live out and demonstrate this love on our own, but with God's help, we can.  If we ask Him, the Spirit of the Living God will transform us day-by-day to become more and more like Him.