King Amaziah did that which was right in the sight of the Lord, but not with a perfect heart (2 Chronicles‬ ‭25:1-2‬). What did King Amaziah do? He overcame his enemies, leading Judah to worship God, but failed to remove the altars of sacrifice and praise for demon gods in the land. He was willing and faithful in carrying out immediate instructions from God, but devoid of the truth of removing abominable influences from the land.

King Solomon was a great king, he obeyed God initially, but lost out in the long run because of entertaining women who believed in false gods. "For it came to pass, when Solomon was old, that his wives turned away his heart after other gods: and his heart was not perfect with the Lord his God, as was the heart of David his father.” (1 Kings‬ ‭11:4‬)‭. He willingly began his relationship with God, but became unfaithful, being led astray from the truth.

We can be right about certain matters and yet be horribly wrong heading towards a disaster. Many Christians willingly go out to 'serve the Lord', and are faithful, but live a lie, having believed a false Jesus. Churches today are being filled with softie Christians, who only want to hear nice things rather than the truth. Churches are turning out to be more entertaining than the world, as the world turns increasingly into a Sodom and Gomorrah.

Many minister, selectively preaching God's word, and provide various attractions to lure the young. Music, used only for worship, has become about performance and emotional manipulation. Tithing and Offerings have been made to look transactional and "profitable". Children and Youth are not being fed the word of God but philosophy and psychology in most cases. Many are preaching the Word of God and still holding onto the World.

Perfection is about fullness, a completeness - having all the parts. To attain that fullness there are two basic emotional traits required, along-with Truth.

There are many other qualities, but I've found these to be a critical need today.

1. Willingness
2. Faithfulness
3. Truth

Willingness

A person is willing when he or she loves or trusts someone or something. When the light shines into our darkness, we willingly choose to be a Christian.

When we do anything willingly, it is accompanied by joy in our hearts, sometimes great joy (1 Chronicles‬ ‭29:9‬). We give our all to it, without a doubt. The sheer pleasure in any activity is a result of our willingness to perform it. We know God loves a cheerful giver (2 Corinthians‬ ‭9:7‬). Any true Christian would give part of his earnings for the work of God, but joyfully, without grumbling or being forced.

Obedience to the Word of God requires a willingness to walk according to the entire Word of God. A decision to walk in Christ needs to come wilfully. No one can convert or force another into a biblical lifestyle. Sinful man is not interested in knowing God, but when he is fed up of life and looks for THE answer, he has a choice to either willingly live for Jesus or choose his own path.

Faithfulness

“And he charged them, saying, Thus shall ye do in the fear of the Lord, faithfully, and with a perfect heart.” (2 Chronicles‬ ‭19:9‬)

Once a man calls himself a Christian, he needs to be faithful in his decision. His lifestyle should reflect the willingness to perform the word of God because of his informed understanding. Without doubt, being faithful in following the doctrines, and instructions, reproving and correcting himself in the word of God. Being an example for others to emulate.

Job was an upright man, perfect in all his ways. Despite losing all his material wealth, and discouraged by his wife's unbelief, he held onto the Word of God, being faithful. He was found perfect before God and man.

Truth

The previous two points reveal necessary attitudes for a Christian. For what? To obey the commandments of God i.e. the Truth.

For the heart to be perfect, it requires the Truth. Devoid of the truth a willing and faithful heart will end up hurting itself. 

Love that is shed abroad in our hearts through the Holy Spirit, rejoices in the truth (1 Corinthians 13:6)

When we hide the truth of the word of God in our hearts, we will not sin against God. (Psalms 119:11). The word of God keeps us from backsliding (Psalms‬ ‭37:31‬). 

Out of the abundance of the heart the mouth speaks. When we live the word of God, our words too will benefit the hearers. (‭‭James‬ ‭3:2‬).

 

When you believe the Word of God to be true, give yourself willingly to perform it and be faithful in every area of your life, in whatever you think, say and do. A perfect heart is positioned to please God on earth that enables entering into eternal life with Him.

Jesus willingly came down to earth, remained faithful to the truth till the very end, fulfilling the will of the Father.