"Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit. O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh." (Matthew 12:33-34)
On our heart
Notice how Jesus starts with the tree that in turn starts with a seed. The roots grow and spread and it could take years before the tree matures and bears fruit. Actually, it does take years. Just know, rewinding down from metaphor, that the things and ways in which we speak are indeed the product of years and years of growing--for good or ill--on our insides. Should we let slip a particular adjective or descriptor (read: epithet) regarding a person, it is the bearing of fruit from a similar seed we ingested God knows when. If the first thought I have regarding someone is rude and derogatory and based on an outward appearance or detail, then my heart, the portion of it reserved for that type of person, is full of weeds. And as we are ourselves are one tree before the Lord, those roots must necessarily be untangled and wound around God. Around the way Jesus looks at people. I will say this, the first thought I seek to have about people I see--male, female, young, old, the spectrum of physical characteristics--is "God please bless this person/that person/everyone all at once." It helps to drown out any attendant thoughts that would seek to be snarky or cynical (a "sin that doth so easily beset [me]" Hebrews 12:1) and that would prevent me from being present should the Holy Spirit decide to move on me to interact in a way foreign to any of my "heart's content".
In our heart
"Let your conversation be without covetousness; and be content with such things as ye have: for He hath said, I will never leave thee, nor forsake thee. So that we may boldly say, The Lord is my helper, and I will not fear what man shall do unto me." (Hebrews 13:5-6)
Now, Jesus also says "for without me ye can do nothing." Earlier on in the verse, He says "I am the vine, ye are the branches: he that abideth in me, and I in him, the same bringeth forth much fruit:" (John 15:5) Is He saying that I am unable breath/open my eyes/get out of bed in the morning without His help? Well, if you wanna get real particular, the third verse of the first chapter of Hebrews says He "uphold[s] all things by the word of His power". The point I'm getting at is that Jesus is the Man. He made our heart and times the beats. He fills us even as we fill a place in His. Do you need more content? Seek Him and "all these things shall be added unto you." (Matthew 6:33) Do you need more contentment? "Rest in the Lord, and wait patiently for Him..." (Psalm 37:7) Jesus delights in us. He loves us so much He gave us the Holy Spirit to move in ways we can't fathom or figure out or even see--to make our hearts one. One with one another and with Him.
Heart to heart