“Seeing ye have purified your souls in obeying the truth through the Spirit unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently: 23Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth forever.” I pe. 1:22-23

Verse 22 says, “love one another with a pure heart fervently.” Verse 23 follows that demand by reiterating that we are born again by an incorruptible seed. The kind of love, “with a pure heart fervently,” is impossible for anyone to do unless they are born again. If you have a hard time loving the brethren from a pure heart and with fervency more than likely it is because you have not really been born again.