My question is: how we know that the feeling of the Holly Ghost is from God, and is not from our own mind wanting us to believe something? I remember a couple of years ago after I read the Book of Mormon and ask God as described in Moroni 10:4, I have a feeling as in Doctrine and Covenants, Section 9:8. I’m less active in the church right now, and I’ve been questioning this to myself lately, if is possible, for example, that after years of studying and participating in the church we feel something about it, but from psychological reasons, or custom rather than the holy spirit. I read in other of your answers, that you suggest reading each page of the Book of Mormon, then ask God every time. As said in Moroni 10:4, having faith is required to ask, how can we tell, if we get an answer, this is from the Holy Spirit or from the faith we have in that we may get an answer?.
This is a very pertinent and fundamental question that you ask, and the answer is not simple. For just a little general background, let’s compare the difference between the scientific method and the theological method of gaining information. The scientific method is based on the principle of doubt. We are not allowed to believe in a concept until it has been proven to be true. Test methods to establish the truth of a given concept generally focus on trying to disprove the thesis. If it cannot be disproved, it is then accepted to be true.
The theological method, on the other hand, is based on the principle of faith. In faith, belief must precede confirmation. In other words, we must act as though we knew that the concept were true. Doing so, we experience the results of our actions. If the concept is indeed true, positive results will ensue. Following this leap of faith, there is the confirmation of the Holy Spirit. This concept gets to the nub of your question. How do we know that we are being influenced by the Holy Spirit, or that we are being swayed by some other influence. The communication from the Holy Spirit is normally very subtle. It is generally experienced as a mild mental impression. In scriptural terms—
And it came to pass when they heard this voice, and beheld that it was not a voice of thunder, neither was it a voice of a great tumultuous noise, but behold, it was a still voice of perfect mildness, as if it had been a whisper, and it did pierce even to the very soul– (Hel 5:30).
And it came to pass that there came a voice unto them, yea, a pleasant voice, as if it were a whisper, saying:
Peace, peace be unto you, because of your faith in my Well Beloved, who was from the foundation of the world (Hel 5:46-47).
When we are trying to hear something whispered, it requires our attention and concentration. When we anticipate an answer from the Lord, it requires our attention and concentration. But what is the nature of that answer? A whisper, although soft, is still an audible sound, detected by the listening ear. God does not speak to our physical beings; He speaks to our spirit. The experience is described well in D&C 8:2-3—
Yea, behold, I will tell you in your mind and in your heart, by the Holy Ghost, which shall come upon you and which shall dwell in your heart.
Now, behold, this is the spirit of revelation; behold, this is the spirit by which Moses brought the children of Israel through the Red Sea on dry ground.
I will tell you in your mind –an idea; and in your heart–a feeling. The example of Moses is cited. Moses had finally convinced the Pharaoh to release the slaves from Goshen into Moses’ custody, and he led them out of the Egypt toward the Sinai peninsula, east of the Red Sea. Now, this was not just a handful of people. Josephus tells us that the total number of people were not counted, but that they included 600,000 men fit for war. The exodus of such a such a major population of slaves would have a severe economic impact on the Egyptian economy, and the Pharaoh soon repented of his coerced decision to free the slaves and sent his army to retrieve them. This army also was not just a small expeditionary force, but it included six hundred chariots, fifty thousand horsemen and two hundred thousand footmen, all armed.. The place where Moses led the children of Israel down to the sea was in a valley between two precipitous mountains.
When they arrived at the water’s edge, late in the afternoon, they saw the Egyptian army appearing over the horizon. They were now trapped, the mountains because of their roughness being impassible, and of course they were without weapons. So Moses appealed to the Lord, with faith, i.e., with full confidence that the Lord would deliver them from the Egyptian army.
As he prayed and pondered, an idea crept into his head–“what if the Lord would just part the waters so that we could just walk over to the other side–” Then came a feeling– “That’s a pretty good idea, Let’s go.” So he started toward the water, signaling to the others to follow, and as he marched into the water, it receded ahead of him, and they marched across. The process–idea, feeling, confident action! However, it may still beg the question, how did he know that the idea and feelings were from the Lord? In the first place, it would be necessary to live near enough to the Lord to be confident that the whisperings were from Him. The feelings would be a confirmation that the idea came from God. For that communication to take place, one must be living a righteous life in faithful accord with the principals of the gospel, such that the Holy Spirit would be his companion.
In your case, when you say that you are less active in the church than you might be, I would suspect that the Holy Spirit may not be your constant companion, and you would be left pretty much on your own to wonder about the process, not knowing whether it was from God or not. As conveyed by Paul—
For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, except he has the Spirit of God (JST 1 Cor 2:11).