“Since you have purified your souls in obeying the truth through the Spirit in sincere love of the brethren, love one another fervently with a pure heart,” 1 Peter 1:22
A purified soul is possible:
Purify your soul by obeying the truth. (Verse 23 says “through the word of God that abides forever.”)
A purified soul is the work of the Holy Spirit.
A purified soul results in sincere, fervent love.
A purified soul expresses itself with an uncontaminated heart.