Nephi taught, “When a man speaketh by the power of the Holy Ghost the power of the Holy Ghost carrieth it unto the hearts of the children of men.” Elder David A. Bednar noted the use of the word unto: “Please notice how the power of the Spirit carries the message unto but not necessarily into the heart. … Ultimately, … the content of a message and the witness of the Holy Ghost penetrate into the heart only if a receiver allows them to enter.”
Why just unto the heart? Individual agency is so sacred that Heavenly Father will never force the human heart, even with all His infinite power. Man may try to do so, but God does not. To put it another way, God allows us to be the guardians, or the gatekeepers, of our own hearts. We must, of our own free will, open our hearts to the Spirit, for He will not force Himself upon us.
("Opening Our Hearts", Gerald N. Lund, April 2008)