I think the Bible teaches you can loose your salvation.  The bible says the following.

1 John 2
3   And hereby we do know that we know him, if we keep his commandments.
4   He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.

I would say we are under the law of Christ now.  The Old Covenant law has passed away.  We how have the perfect law of liberity, the royal law or the law of Christ.  This law is layed out in the New Covanent.

"and there is nothing you  can do to lose it." I think if you go and wilfully disobey a known commandment of God you are not longer part of God's kingdom.  While I have read books from both sides I think the bible is clear that the soul that sins shall die.  That is spiritual death.

We are not saved by works but when we are saved we will have words.  Faith with out works is dead.

1 John 2:3,4
And hereby we do know that we know him, if we keep his commandments.
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
We don't obtain salvation keeping the commandments of the bible.  For by grace are ye saved though faith, not of works.  But when we are truely converted we will by the power of God keep his commandments.  If some one says they know him and don't keep his commandments the bible says they are a liar and the truth is not in him.

Men should have short hair.  The pictures of Jesus are incorrect in my mind when they show him with shoulder length hair.  The Roman Leaders of Jesus day had hair over there ears and people following what they did as the people thought they were gods.  So I am all for short hair.

The long hair for sisters.  If a womens hair is her glory and given to her for a covering I would say she shouldn't cut her glory off.