For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation (Romans 10:10 KJV)
We believe with our hearts. The heart in this verse refers to our inner life, and that inner life generally is made up of the spirit and the soul. To maintain brevity, the heart here means all the capacities within you: thoughts(reason) with associated consciousness and conscience, emotions, and the will. I will not discuss spirit and soul here for brevity so please watch the appropriate FREE teachings we have on this.
God is saying that you believe the Word by using your heart, the capacities listed above, mainly through your reason and then the will and also the emotions to some degree. Believing means accepting as truth and relying upon it. You judge information using your reason(thoughts), accept or reject it(will) and even become persuaded about it(emotions).
The heart here does not mean the human spirit exclusively, that is, we believe with our spirit only. I have taught extensively about this error, which is responsible for a great deal of our confusion and immaturity in faith.
The Lexham Survey of Theology makes this comment regarding the capacity for thought called “reason” : “while reason and faith are often thought to be opposed to one another, the Christian gospel comes in human language; it is meant to be received by being understood (1 Cor 14:9)”.
You believe God with your heart, and that is under your control. The heart is not something mystical inside you that you have no control over.
What is the meaning of the term “heart” above? Do you have two distinct capacities within you to believe, one with our spirit and another with your soul?
Apply the Word
You can search your heart and know if you have believed. Faith is not something in a strange mystical spirit realm in us that is beyond our grip. Train your heart to believe the Word. That will be Glory & Grace Live Bible study later tonight.
Ask the Father to help you undershot fully what it means to believe and how to grow in it.