Christian Love.
I. Purity: "Love one another with a pure heart fervently." (1) The word for purified in this verse is not that denoting the infusion of virtue, but that which signifies the expulsion from the soul of all defilement, and especially of selfishness. (2) The way to secure this is by believing obedience to the truth as revealed in the Gospel.
II. Unfeignedness: "unfeigned love of the brethren" genuine love, without dissimulation, free from hypocrisy. (1) We read of faith unfeigned that is, faith which is firm and solid to the core. (2) Love unfeigned is love which will not give way under trial, that will suffer a burden to be put on its back.
III. Fervour: "with a pure heart fervently." This implies that our love of the brethren should be powerful enough (1) to overcome all sinful obstacles in our nature, (2) to overcome all national and sectarian differences.
J. C. Jones, Studies in First Peter,p. 170.
References: 1 Peter 1:23. Spurgeon, Evening by Evening,p. 125; Homilist,2nd series, vol. i., p. 325.