The word 'muse' is used only a couple of times in scripture. To muse is to ponder deeply or to be absorbed in thought. King David wrote that he meditated on the creations of God or 'muse[d] on the work of thy hands' (Psalm 143:5). As he pondered on truth, his 'heart was hot within [him], while I was musing the fire burned' as he felt the Holy Ghost confirm truth to his soul (Psalm 39:3). Perhaps it was a similar confirmation that the Jews sought when they, 'mused in their hearts of John [the Baptist], whether he were the Christ, or not' (Luke 3:15).
One of the fundamental principles of the gospel is that there is an absolute truth. All things that are true are necessarily consistent with all other things that are true; truth can be circumscribed into one great whole. The inevitable consequence of this principle is that the truths that bless our lives may be found in scripture, in physics, in philosophy, in anatomy, in mathematics, or, among many other places, in grammar.
A member of my church congregation pointed out one of the lessons we can learn from grammar in a recent testimony. He reminded us that adding an 'a' to the beginning of a word changes the meaning of the word to its opposite: so something apolitical is not political; something that is asymmetrical lacks symmetry; and something that is atypical is anything but typical.
Applied to the word 'muse', grammar teaches us that the opposite of pondering and meditation is amusement. Rather than the deep, soul searching thoughts of musing, amusing implies shallow, fleeting thoughts on topics of trivial value.
Though some amusement may be fun and useful in relieving stress or bringing temporary satisfaction, it is unlikely to precede revelation or bring us closer to God in the same way that its antithesis, musing, can. Elder Dallin H. Oaks has taught:
Our priorities are most visible in how we use our time. Someone has said, 'Three things never come back--the spent arrow, the spoken word, and the lost opportunity.'... Good choices are especially important in our family life. For example, how do family members spend their free time together? Time together is necessary but not sufficient. Priorities should govern us in the precious time we give to our family relationships. Compare the impact of time spent merely in the same room as spectators for television viewing with the significance of time spent communicating with one another individually and as a family.
To cite another example, how much time does a family allocate to learning the gospel by scripture study and parental teachings, in contrast to the time family members spend viewing sports contests, talk shows, or soap operas? I believe many of us are overnourished on entertainment junk food and undernourished on the bread of life...
A decade later, Elder Ian S. Ardern added his testimony:
I know our greatest happiness comes as we tune in to the Lord (see Alma 37:37) and to those things which bring a lasting reward, rather than mindlessly tuning in to countless hours of status updates, internet farming, and catapulting angry birds at concrete walls. I urge each of us to take those things which rob us of precious time and determine to be their master, rather than allowing them through their addictive nature to be the master of us.
'Muse' is not a very common word in the modern American vocabulary. The member of my congregation, Elder Oaks, Elder Ardern, and other inspired voices have counseled us all to make it more common in our private lives and vocabularies. Exactly when and how would work best for you-- well, that might be your first reason to push an 'a' aside and start musing.