This is the poster child verse used by critics and anti-Mormons of the promise to receive a spiritual witness of the truthfulness of the Book of Mormon or other truths.
9 The heart is deceitful above all things, and desperately wicked: who can know it? Jer 17:9
The two main verses uniquely used by Latter-day Saints to push us to seek the Spirit and revelation in our lives are probably as follows:
3 Behold, I would exhort you that when ye shall read these things, if it be wisdom in God that ye should read them, that ye would remember how merciful the Lord hath been unto the children of men, from the creation of Adam even down until the time that ye shall receive these things, and ponder it in your hearts.
4 And when ye shall receive these things, I would exhort you that ye would ask God, the Eternal Father, in the name of Christ, if these things are not true; and if ye shall ask with a sincere heart, with real intent, having faith in Christ, he will manifest the truth of it unto you, by the power of the Holy Ghost.
5 And by the power of the Holy Ghost ye may know the truth of all things.
D&C 9:7-9Now, lest the anti's think the Mormons are the only ones who think the witness of the Spirit is something physical, here is an excerpt from Netbible's commentary for Rom 8:16:
7 Behold, you have not understood; you have supposed that I would give it unto you, when you took no thought save it was to ask me.
8 But, behold, I say unto you, that you must study it out in your mind; then you must ask me if it be right, and if it is right I will cause that your bosom shall burn within you; therefore, you shall feel that it is right.
9 But if it be not right you shall have no such feelings, but you shall have a stupor of thought that shall cause you to forget the thing which is wrong; therefore, you cannot write that which is sacred save it be given you from me.
"In sum, Rom 8:16 seems to be secure as a text in which the believer’s assurance of salvation is based on the inner witness of the Spirit. The implications of this for one’s soteriology are profound: The objective data, as helpful as they are, cannot by themselves provide assurance of salvation; the believer also needs (and receives) an existential, ongoing encounter with God’s Spirit in order to gain that familial comfort.”" Here is the entire citation.
What is so controversial they spend a paragraph carefully explaining the grammar?
The Spirit himself bears witness to [fn 1] our spirit that we are God’s children.(Rom 8:16)I have previously written elsewhere fairly extensively on this subject. It is simply an absurdity to claim the Bible does not teach that the normal manner of God to communicate with his children is something other than tangible feelings communicated to men, typically described as the heart.
We have the citation of Romans 8:16 above with comments by the non-LDS translator explaining that the witness described there is an existential. That means something they actually experience, something which exists.
But let's turn to the Bible, and specifically to Jeremiah. Jeremiah uses the word "heart" 52 times. So here comes something not shocking to anyone who has actually read Jeremiah: He almost always uses it in a positive context (such as turning from an evil heart to a good heart, or having a good heart, or talking about God's heart), but there are 16 instances where the heart is described as evil. That this is about people who are of evil intentions and not the state of all humans is pretty obvious:
13 And ye shall seek me, and find me, when ye shall search for me with all your heart.
7 And I will give them an heart to know me, that I am the LORD: and they shall be my people, and I will be their God: for they shall return unto me with their whole heart.
Jer 15:16What about that whole "burning heart" thing in Luke? Check Jeremiah first:
16 Thy words were found, and I did eat them; and thy word was unto me the joy and rejoicing of mine heart: for I am called by thy name, O LORD God of hosts.
Jer 20:9What about elsewhere in the Bible, how is an open mind received, or how does God communicate to people?
9 Then I said, I will not make mention of him, nor speak any more in his name. But his word was in mine heart as a burning fire shut up in my bones, and I was weary with forbearing, and I could not stay.
2 Chr 34:27
27 Because thine heart was tender, and thou didst humble thyself before God, when thou heardest his words against this place, and against the inhabitants thereof, and humbledst thyself before me, and didst rend thy clothes, and weep before me; I have even heard thee also, saith the LORD.
11 ¶ Thy word have I hid in mine heart, that I might not sin against thee.
58 ¶ I intreated thy favour with [my] whole heart: be merciful unto me according to thy word.
12 ¶ Apply thine heart unto instruction, and thine ears to the words of knowledge.
Of course, it is worth asking who gave Solomon his wisdom, and where was it communicated to him?
2 Chr 9:23So let's start to wrap this up, as it is obvious that God does speak to our heart, and it is not always a false or deceptive spirit talking to us, though we can deceive ourselves.
23 And all the kings of the earth sought the presence of Solomon, to hear his wisdom, that God had put in his heart.
2 If ye will not hear, and if ye will not lay it to heart, to give glory unto my name, saith the LORD of hosts, I will even send a curse upon you, and I will curse your blessings: yea, I have cursed them already, because ye do not lay it to heart.
Luke 24:32The footnote in the Netbible says of Luke 24:32
32 And they said one to another, Did not our heart burn within us, while he talked with us by the way, and while he opened to us the scriptures?
87 tn This is a collective singular use of the term καρδία (kardia), so each of their hearts were burning, a reference itself to the intense emotion of their response.
1 Cor 2:14How are the things of God discerned? Spiritually. So what does discerned mean? Judge by investigation. How does one spiritually "judge by investigation"? Here are multiple translations:
14 But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.
NET Bible 1Cor 2:14 The unbeliever does not receive the things of the Spirit of God, for they are foolishness to him. And he cannot understand them, because they are spiritually discerned.So...is there anyone unclear on how the things of God are understood? If it was just a matter, as Shawn McCraney represents, of looking at physical evidence and determining it is true, anyone could do that. Paul says that is not the case. Spirit to spirit revelation is how one comes to know of spiritual things.
NIV 1Co 2:14 The man without the Spirit does not accept the things that come from the Spirit of God, for they are foolishness to him, and he cannot understand them, because they are spiritually discerned.
NASB 1Co 2:14 But a natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually appraised.
NLT 1Co 2:14 But people who aren’t Christians can’t understand these truths from God’s Spirit. It all sounds foolish to them because only those who have the Spirit can understand what the Spirit means.
MSG 1Co 2:14 The unspiritual self, just as it is by nature, can't receive the gifts of God's Spirit. There's no capacity for them. They seem like so much silliness. Spirit can be known only by spirit--God's Spirit and our spirits in open communion.
BBE 1Co 2:14 For the natural man is not able to take in the things of the Spirit of God: for they seem foolish to him, and he is not able to have knowledge of them, because such knowledge comes only through the Spirit.
NRSV 1Co 2:14 Those who are unspiritual do not receive the gifts of God’s Spirit, for they are foolishness to them, and they are unable to understand them because they are spiritually discerned.
NKJV 1Co 2:14 But the natural man does not receive the things of the Spirit of God, for they are foolishness to him; nor can he know them , because they are spiritually discerned.
1 Cor 12:3 ...no man can say that Jesus is the Lord, but by the Holy Ghost.If not by spirit to spirit communication, then what is the way which is not understood by those without the Spirit?
In the end, we find out that the heart of the unrepentant, wicked and proud people are in fact incapable of understanding the Spirit, but it is not because EVERYONE is beyond experiencing the things of the Spirit.
Eph 4:17-23Saying that all are in possession of desperately wicked hearts and that God does not communicate through the medium of feelings is thoroughly refuted by even a cursory examination of the Bible, and is embarrassingly so for those who actually study the context of passages such as the constantly perverted passage out of Jeremiah.
17 ¶ This I say therefore, and testify in the Lord, that ye henceforth walk not as other Gentiles walk, in the vanity of their mind,
18 Having the understanding darkened, being alienated from the life of God through the ignorance that is in them, because of the blindness of their heart:
19 Who being past feeling have given themselves over unto lasciviousness, to work all uncleanness with greediness.
20 But ye have not so learned Christ; 21 If so be that ye have heard him, and have been taught by him, as the truth is in Jesus: 22 That ye put off concerning the former conversation the old man, which is corrupt according to the deceitful lusts; 23 And be renewed in the spirit of your mind;
Of course, bringing this up is almost a vanity blog, since the most vocal critics are the least likely to receive by the Spirit the witness contained in the passages mentioned here.