8 But what does it say? “The word is near you, in your mouth and in your heart” (that is, the word of faith that we proclaim);
9 because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved.
10 For with the heart one believes and is justified, and with the mouth one confesses and is saved. – Romans 10:8-10
The word is in you. What a wonderful promise. We have the Word of God in us by the power of the Holy Sprit:
And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” – Galatians 4:6
and who has also put his seal on us and given us his Spirit in our hearts as a guarantee. – 2 Corinthians 1:22
In your mouth and in your heart, Christ living in us:
so that Christ may dwell in your hearts through faith – that you, being rooted and grounded in love, – Ephesians 3:17
We are the temple of the Holy Spirit:
Do you not know that you are God’s temple and that God’s Spirit dwells in you? – 1 Corinthians 3:16
All this reassures is that God dwells with us as he promised:
19 And I will give them one heart, and a new spirit I will put within them. I will remove the heart of stone from their flesh and give them a heart of flesh,
20 that they may walk in my statutes and keep my rules and obey them. And they shall be my people, and I will be their God. – Ezekiel 11:19-20
And this leads to the great revelation that if we confess with our mouth the Lord Jesus and believe in our heart God raised Him from the dead we will be saved. The centre of our ability to have faith and believe is our heart not our mind. We may come to faith by hearing and analysing the truth of the gospel but it is our heart that is the powerhouse of our passion and desire to know God and believe in Him.
Keep your heart with all diligence, For out of it [spring] the issues of life. -Proverbs 4:23 (NKJV)
But, the heart is deceptive:
9 The heart is deceitful above all things, and desperately sick; who can understand it?
10 “I the LORD search the heart and test the mind, to give every man according to his ways, according to the fruit of his deeds.” – Jeremiah 17:9-10
1 The fool says in his heart, “There is no God.” They are corrupt, they do abominable deeds; there is none who does good.
2 The LORD looks down from heaven on the children of man, to see if there are any who understand, who seek after God.
3 They have all turned aside; together they have become corrupt; there is none who does good, not even one. – Psalm 14:1-3
The heart can be the very place that we reject God and decide to live for ourselves.
So, what is the outward sign that we have accepted Christ into our heart? What we confess, what we say with our mouth. If we confess that Jesus is our Lord. If we declare openly that Jesus is our saviour, redeemer, and friend. He is Lord and as we tell others we are identifying with Him. Christ dwells in our heart by faith and through that faith, that belief, we are justified. And with our mouth we confess our love for Him and share the gospel with the lost and dying world that they might also be saved.