The idea that Christians cannot sin, which state the often arrogant Masters claims for himself, has been refuted before, but the assertion that they do not is simply repeated.
"If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. " (1 John 1:8-9)
The “we” here includes Christians, and does not refer to being simply sinners by nature, or our past life.
"For in many things we offend all." (James 3:2a)
"But when Peter was come to Antioch, I withstood him to the face, because he was to be blamed. For before that certain came from James, he did eat with the Gentiles: but when they were come, he withdrew and separated himself, fearing them which were of the circumcision. And the other Jews dissembled likewise with him; insomuch that Barnabas also was carried away with their dissimulation [duplicity, hypocrisy]" (Galatians 2:11-13)
1Jn 3:4 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.
The Greek scholar Robertson states,
The present active participle (poiōn) means the habit of doing sin.
1Jn 3:6 Whosoever abideth in him sinneth not: whosoever sinneth hath not seen him, neither known him.
Sinneth not (ouch hamartanei). Linear present (linear menōn, keeps on abiding) active indicative of hamartanō, “does not keep on sinning.” For menō (abide) see 1Jo_2:6; Joh_15:4-10.
Whosoever sinneth (ho hamartanōn). Present (linear) active articular participle like menōn above, “the one who keeps on sinning” (lives a life of sin, not mere occasional acts of sin as hamartēsas, aorist active participle, would mean).
Hath not seen him (ouch heōraken auton). Perfect active indicative of horaō. The habit of sin is proof that one has not the vision or the knowledge (egnōken, perfect active also) of Christ. He means, of course, spiritual vision and spiritual knowledge, not the literal sense of horaō in Joh_1:18; Joh_20:29.(WORD PICTURES IN THE NEW TESTAMENT by Archibald Thomas Robertson)
"Little children, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous. He that committeth sin is of the devil; for the devil sinneth from the beginning." (1Jn. 3:7,8)
We see here that John is not speaking in an absolute sense, but as regards overall characteristics, as the lost can do things that are objectively righteous, such as feeding his brethren who are needy, while as seen in Gal. 2:11-13, Christians do sin.
To be perfect, as loving your enemies, blessing them that curse you, doing good to them that hate you, is commanded (Mt. 5:48) and perfection in abiding in Christ by longsuffering faith throughout all trials and temptations, (Heb. 2:10; 5:9; 1Pt. 1:6,7) and not offending in word, (Ja. 3:2) keeping His word and and only serving out of love-motivation, (Jn. 2:5; 4:17,18) is a goal of grace, fulfilling the righteousness of the law. (Rm. 8:4)
But this state is not that of being being born again as Masters teaches, but which occurs in conversion, (Acts 10:43-47; 15:8,9; Eph. 1:13) nor is achieving this a prerequisite for being a Christian and saved, as “God justifies the UnGodly by faith,” (Rm. 4:5) but who evidence that faith as salvific by growing in grace with its fruits, especially in effectual love for the brethren. (Heb. 6:9,10)
For "The Lord is nigh unto them that are of a broken heart; and saveth such as be of a contrite spirit," (Psalms 34:18) and it cannot be said that the criminal on the cross, who went to be with the Lord the same day that he died, (Lk. 23:39-43) had attained perfection of character, nor were all the Thessalonians and Corinthians practically perfect, yet they were told that they would forever be with the Lord had He returned in their day, (1Thes. 4:17), except such as had "not repented of the uncleanness and fornication and lasciviousness which they have committed." (2Cor. 12:21)
Thus they were to examine themselves, whether they were in the faith, (2Cor. 13:5) their lives being characterized by walking in obedience to Christ by the Spirit, doing righteousness as John describes them, and which includes repentance when convicted of not doing do. (1Jn. 1:8,9; Rv. 2:1-6) As true faith is repentant, and this is necessary, so God works to chastens believers back to faith as necessary, so that they will not be condemned with the rest of the world, and also motivates this by warning of making Christ of none effect by falling away. (1Cor. 11:32; cf. Gal. 5:1-4; Heb. 10:35-39) While true faith versus false faith may not always be clearly manifest, 1Jn. describe the overall characteristics of those who have eternal life, which 1Jn. 5:13 refers to, including confessing sin.
Further testimony that complete perfection of character is not a requirement for salvation is seen by the fact that some believers will suffer loss of rewards at the judgment seat of Christ (at His return), because some of the material which they built the church with, insomuch as they did, did not endure the fire which tests faith. And which is a reflection of their character. See my understanding here on 1Cor. 3:8-17 (and which also does not refer to purgatory).
Lot is called righteous Lot in spite of his gross sin.
Psalm 103:13&14
13 As a father shows compassion to his children, so the Lord shows compassion to those who fear him. 14 For he knows our frame; he remembers that we are dust.