Spencer W. Kimball
"This passage indicates an attitude which is basic to the sanctification we should all be seeking, and thus to the repentance which merits forgiveness. It is that the former transgressor must have reached a ‘point of no return’ to sin wherein there is not merely a renunciation but also a deep abhorrence of the sin where the sin becomes most distasteful to him and where the desire or urge to sin is cleared out of his life.
"Surely this is what is meant, in part at least, by being pure in heart! And when we read in the Sermon on the Mount that the ‘pure in heart’ shall see God, it gives meaning to the Lord’s statement, made through the Prophet Joseph Smith in 1832, that presently impure people can perfect themselves and become pure:
’Therefore, sanctify yourselves that your minds become single to God, and the days will come that you shall see him; for he will unveil his face unto you, and it shall be in his own time, and in his own way, and according to his own will.’ (D&C 88:68.)"
(The Miracle of Forgiveness, pp. 354-5)