From hagnos; to make clean, i.e. (figuratively) sanctify (ceremonially or morally) -- purify (self).
see GREEK hagnos
1. ceremonially: ἐμαυτόν, John 11:55 (to cleanse themselves from levitical pollution by means of prayers, abstinence, washings, sacrifices); the passive has a reflexive force, to take upon oneself a purification, Acts 21:24, 26; Acts 24:18 (הזּיר, Numbers 6:3), and is used of Nazarites or those who had taken upon themselves a temporary or a life-long vow to abstain from wine and all kinds of intoxicating drink, from every defilement and from shaving the head (cf. BB. DD. under the word 2. morally: τάς καρδίας, James 4:8; τάς ψυχάς, 1 Peter 1:22; ἑαυτόν, 1 John 3:3. (Sophocles, Euripides, Plutarch, others.)