The heart.

Your heart is the core of your being  It is part soul, part spirit and intimately connected to your body -  in some ways it defines your essence.  It needs love and, if there is a love deficit, craves it.  The heart is that part of you that motivates you (along with body and soul).  It is where your deepest self resides and, incidentally, it is where God resides in you.  Your own heart can be your ally or your enemy,

The Bible says, "Keep your heart with all diligence;  for out of it spring the issues of life." (Proverbs 4:23).  Your heart can drive you to extreme actions (good and bad) and into sin.  Your heart is key because if motivates you in the deepest ways.  A heart for the lost can drive a person to preach, a heart for the hurting, to minister healing.  A heart in need of love can drive you to seek love in God and/or in other and to activities (helpful or unhelpful, divine or depraved) to help fill the void in any way it can.

Do the very best you can to keep you heart safe.  Fill it with the right things.  Cravings for love can lead to relationships and sexual immorality or activities/addictions that feel good, that bring you moments of peace and momentary happiness, but which actually "war against the soul" (1 Peter 2:11).  Instead of healing, you'll be compelled to endure more heartbreak and yearning and distance from God.  That is Satan's plan.  He wants your soul.  He works endlessly to damage you more every day.

Another issue with the human heart is that your mouth speaks what's inside your heart (Matthew 12:13).  What comes from your mouth mixed with faith becomes reality.  That's good news and bad news (if your faith in God is not robust).  Because of this, it is vital to maintain your heart in right condition so you don't end up snared by your own words.

What lies within your heart has other effects.  The negative things in your heart and their resulting actions will limit you from receiving freedom, gifts and blessings that God has for you and will also keep you from transferring them to others.

Anything that is beneficial and anything that is evil that exists in your life will (to one degree of another) manifest in results - logical results based on spiritual laws and the principals in operation within the spirit world.  Your heart is an integral part of what is in your life.  Your thoughts, beliefs and actions serve to open and/or close spiritual doors and windows, for good or evil in your life, in the lives of others, and to those under you authority.  The results are often difficult to predict.

Always do the best you can.  Spend time diligently filling your heart with the Word of God and the teachings based on it; don't let them depart from your eyes or heart (Proverbs 4:20-22).  Spend time in the morning reading the Bible and praying, then listen to Christian music to resist evil and realize that you do not have to do the ungodly things that flash through your mind like litter in a hurricane.  If you think you HAVE to do something ungodly, your heart is beguiled by Satan.  In some ways, the beginning of deliverance is realizing that you don't HAVE to do the tawdry things your heart craves.  Even if you're addicted to something or someone, you do not have to indulge; but you do have to be treated for your addiction to see this truth and regain the power and authority to abandon the practice.

So, beware of what is in your heart.  The Bible says in Ecclesiastes 9:3 that there is madness in it.  Ask God to help you with it, to fill it with Himself and to heal it.