Bruce R. McConkie
"'For behold, God hath said a man being evil cannot do that which is good; for if he offereth a gift, or prayeth unto God, except he shall do it with real intent it profiteth him nothing. For behold, it is not counted unto him for righteousness .... And likewise also is it counted evil unto a man, if he shall pray and not with real intent of heart; yea, and it profiteth him nothing, for God receiveth none such.' (Moro. 7:6-9.) Rather men are commanded to 'pray unto the Father with all the energy' of their hearts, with all the strength that their whole souls possess. (Moro. 7:48.)
"…'Do not pray as the Zoramites do, for ye have seen that they pray to be heard of men, and to be praised for their wisdom. Do not say: O God, I thank thee that we are better than our brethren; but rather say: O Lord, forgive my unworthiness, and remember my brethren in mercy -- yea, acknowledge your unworthiness before God at all times.' (Alma 38:13-14.) Further: 'Pray for them who despitefully use you and persecute you.' (3 Ne. 12:44; Matt. 5:44.)
"Those formal, written prayers which are commonly read by ministers, and those recited by lay church members in doing penance or seeking grace, are devoid of the true spirit of prayer and should be shunned. Frequently they are spoken without real intent; and their use keeps men from searching their own hearts in an attempt to pray in faith according to an approved pattern so that actual blessings may be gained from Deity. Not infrequently these prepared prayers are read, recited, or chanted in ritualistic ceremonies in which the speakers do not concentrate all the faculties of their whole souls upon the prayers being offered. As a consequence the words often take on the nature of useless jargon and do not open the door to the receipt of the Lord's blessings." (Mormon Doctrine, p. 585)
Charles W. Penrose
"Now, prayer is not acceptable for its rhetoric. It is that which comes from the heart, the sincere sentiment, the secret feeling, which ascends to our Father and which He, who sees in secret, will reward openly. It is not a multitude of words and repetitions that is pleasing to the Lord, but the earnest desire of a humble heart. And this will be answered, no matter how broken or ungrammatical the language may be. On the other hand, no matter how flowery the language of the petition may be, if it does not convey the feelings of the heart, it is not true prayer." (Collected Discourses 1886-1898, ed. by Brian Stuy, vol. 2, Charles W. Penrose, March 22, 1891)