Bruce R. McConkie
"Boasting is of two kinds: either righteous, or unrighteous; either in the arm of flesh, or in the Lord and his gracious goodness and power. ’He that glorieth, let him glory in the Lord,’ Paul said in summing up a sermon on boasting, ’For not he that commendeth himself is approved, but whom the Lord commendeth.’ (2 Cor. 10:7-18; Ps. 44:8.) Ammon spoke similarly: ’I do not boast in my own strength, nor in my own wisdom; but behold, my joy is full, yea, my heart is brim with joy, and I will rejoice in my God. Yea, I know that I am nothing; as to my strength I am weak; therefore I will not boast of myself but I will boast of my God, for in his strength I can do all things. Therefore, let us glory, yea, we will glory in the Lord; yea, we will rejoice for our joy is full; yea, we will praise our God forever. Behold, who can glory too much in the Lord?’ (Alma 26:8-16, 35.)
"Boasting in the arm of flesh, one of the commonest of all sins among worldly people, is a gross evil; it is a sin born of pride, a sin that creates a frame of mind which keeps men from turning to the Lord and accepting his saving grace. When a man engages in self exultation because of his riches, his political power, his worldly learning, his physical prowess, his business acumen, or even his works of righteousness, he is not in tune with the Spirit of the Lord. Salvation itself comes by the grace of God, ’Not of works,’ that is not of the performances and outward display of the law, ’lest any man should boast.’ (Eph. 2:4-22; Rom. 3:27.) As King Benjamin asked, after explaining the goodness of God and the comparative nothingness of men, ’Of what have ye to boast?’ (Mosiah 2: 17-26.)
“Even when the righteous glory in the Lord, certain very definite restrictions attend their godly boasting. The elders are to proclaim against evil spirits, but ’Not with railing accusation, that ye be not overcome, neither with boasting nor rejoicing, lest you be seized therewith.’ (D. & C. 50:32-33.) Spiritual gifts are poured out abundantly upon the true saints. ’But a commandment I give unto them,’ the Lord says, ’that they shall not boast themselves of these things, neither speak them before the world; for these things are given unto you for your profit and for salvation.’ (D. & C. 84:73.) ’Talk not of judgments, neither boast of faith nor of mighty works.’ (D. & C. 105:24.)” (Mormon Doctrine, p. 93)