John 7:24 KJVS
Judge not according to the appearance, but judge righteous judgment.
Matthew 7:15 KJVS
Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
When we say our works, whether appearing good or bad, can be evidences of our salvation, we make ourselves susceptible to false brethren creeping in unawares. It is akin to sheep telling other sheep that the wolf is ok because he is wearing sheep's skin. No, we need to use more surefire criteria of who we may call brethren.
We therefore judge rightly when we judge based on one's confession of true gospel propositions, ALL of them! It is not outward morality nor should it ever be as it has the potential to be VERY deceptive. Just as our assurance is in Christ, not works, likewise our evidences should be in that he immutably and miraculously CAUSED us to believe a gospel of which our minds were formerly blind.
John 6:29-40 KJVS Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.  They said therefore unto him, What sign shewest thou then, that we may see, and believe thee? what dost thou work?  Our fathers did eat manna in the desert; as it is written, He gave them bread from heaven to eat.  Then Jesus said unto them, Verily, verily, I say unto you, Moses gave you not that bread from heaven; but my Father giveth you the true bread from heaven.  For the bread of God is he which cometh down from heaven, and giveth life unto the world.  Then said they unto him, Lord, evermore give us this bread.  And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.  But I said unto you, That ye also have seen me, and believe not.  All that the Father giveth me shall come to me; and him that cometh to me I will in no wise cast out.  For I came down from heaven, not to do mine own will, but the will of him that sent me.  And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day.  And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day.