"Above all else, guard your heart, for everything you do flows from it." (Proverbs 4:23)  The  breastplate obviously covers the heart.  Physically, the heart is a vital mechanical pump; but it is a metaphor for the part of us that holds desires and makes decisions.  We may think that we decide with logic and objectivity, but we don't!  The big decisions of who to marry, what job to accept and where to live - are not just the product of logic but the combination of what we want and what we can get.  The same process occurs in falling into temptation (James 1:13-15), so we know that Satan is expert at setting us up to fail.  That is why we need the Lord's armour to protect our hearts.

Part of that armour is the breastplate of righteousness.  Being in the right matters to human beings more than most realise.  God has created us to be at one with Him, enjoying His protection because we are close to Him.  But if we ignore Him and persist in wanting what is not right, He will eventually allow us to suffer the consequences of our wrong desires (Psalm 106:15).   That is why it is crucial that our hearts are protected as we practise loving God and working in fellowship with Him - otherwise we open a gap for evil to attack us and we will have no defence.

Even God puts on a breastplate of righteousness (Isaiah 59:17), and every believer must do the same.  The righteousness is God's righteousness.  Only He can define what is right.  That right belief, thinking, desire and action comes as the Holy Spirit used the Word to show us what is wrong in our lives and uses it to change us to be like Jesus.  Only that kind of righteousness is an adequate defence against Satan. If we look to our own integrity, skill and power, the devil will find many weak points through which he can wound us fatally.  But if we are submitting ourselves to the authority of the Lord Jesus, God gives us His righteousness (Romans 3:22).  More than that, Jesus becomes our righteousness (1 Corinthians 1:30).  It is as though Jesus Himself stands in front of us, so close to our hearts, to protect our hearts and deter the Evil One.

We must choose to accept what is right according to Jesus as the resource for our hearts.  However, the world of work often has a different agenda: short term battles instead of eternal victory; pragmatism instead of principles; and convenience instead of conscience.  So, to march out into a new day with Jesus in front of you will be very different.  It will matter to you what is right, because it matters to Jesus.  It will be important not to make wrong decisions because it would grieve Jesus.  And even when the pace of life becomes so rapid that we hardly know what decisions we are making - those who have the righteousness of Christ covering their hearts will have an internal hunger to choose the right, knowing that their Heavenly Father will meet their needs (Matthew 5:6).  When that happens, there is no place for evil to reach through to wound our hearts.  Put on that breastplate today - if God does, we certainly need to!