A.T. Robertson Commentary 1 Peter 1:22

"Seeing ye have purified your souls in your obedience to the truth unto unfeigned love of the brethren, love one another from the heart fervently:" — 1 Peter 1:22 (ASV)

Seeing ye have purified (ηγνικοτες). Perfect active participle of αγνιζω, old verb from αγνος (pure), here with ψυχας (souls), with καρδιας (hearts) in Jas 4:8 as in 1 John 3:3 of moral cleansing also. See the ceremonial sense of the word as in LXX in Joh 11:55; Acts 21:24,26; 24:18.

In your obedience (εν τη υπακοη). With repetition of the idea in 1:2,14 (children of obedience).

To the truth (της αλεθειας). Objective genitive with which compare Joh 17:17,19 about sanctification in the truth and 2 Thessalonians 2:12 about believing the truth. There is cleansing power in the truth of God in Christ.

Unfeigned (ανυποκριτον). Late and rare double compound, here alone in Peter, but see Jas 3:17; 2 Corinthians 6:6, etc. No other kind of φιλαδελφια (brotherly love) is worth having (1 Thessalonians 4:9; Hebrews 13:1; 2 Peter 1:7).

From the heart fervently (εκ καρδιας εκτενως). Late adverb (in inscriptions, Polybius, LXX). The adjective εκτενης is more common (1 Peter 4:8).