...nor do i see failing to observe sabbath listed as a work of flesh.
galatians 5:13 For you, brethren, have been called to liberty; only do not use liberty as an opportunity for the flesh, but through love serve one another....
It is because you are willingly blind, and choose not to see:
Walking in "liberty", is to walk apart from sin (1 John 3:4) and in obedience to God's commandments, for sin (1 John 3:4) is slavery, bondage (see God called people out of "bondage", Exodus 20:1-2, that they may be free, Exodus 20:2-17):
Psalms 119:41 VAU. Let thy mercies come also unto me, O LORD, even
thy salvation, according to
thy word.
Psalms 119:42 So shall I have wherewith to answer him that reproacheth me: for I trust in
thy word.
Psalms 119:43 And take not
the word of truth utterly out of my mouth; for I have hoped in thy judgments.
Psalms 119:44 So shall I
keep thy law continually for ever and ever.
Psalms 119:45
And I will walk at liberty: for I seek thy precepts.
Psalms 119:46 I will speak of thy testimonies also before kings, and will not be ashamed.
Psalms 119:47 And I will delight myself in
thy commandments, which I have loved.
Psalms 119:48 My hands also will I lift up unto
thy commandments, which I have loved; and I will meditate in thy statutes.
Law of "liberty", is God's Commandments:
James 1:22 But
be ye doers of the word, and
not hearers only,
deceiving your own selves.
James 1:23 For if any be a hearer of the word, and not a doer, he is like unto a man beholding his natural face in a glass:
James 1:24 For he beholdeth himself, and goeth his way, and straightway forgetteth what manner of man he was.
James 1:25 But whoso looketh into
the perfect law of liberty, and continueth therein, he being not a forgetful hearer, but
a doer of the work, this man shall be blessed in his deed.
The Ten Commandments are the Law of the King/Priests:
James 2:8 If ye fulfil
the royal law according to the scripture, Thou shalt
love thy neighbour as thyself, ye do well:
James 2:9 But if ye have respect to persons, ye commit sin, and are convinced of
the law as transgressors.
James 2:10 For whosoever shall
keep the whole law, and yet offend in one point, he is guilty of all.
James 2:11 For he that said,
Do not commit adultery, said also, Do not kill. Now if thou commit no adultery, yet if thou kill, thou art become a transgressor of
the law.
James 2:12 So speak ye, and so do, as they that shall be
judged by the law of liberty.
Sin (1 John 3:4) is the bondage:
Acts 8:23 For I perceive that thou art in the gall of bitterness, and in
the bond of iniquity.
God's grace leads out of bondage of sin (1 John 3:4) into obedience to His will (Psalms 40:8):
Exodus 20:2 I am the LORD thy God, which have brought thee out of the land of Egypt,
out of the house of bondage.
Deuteronomy 5:6 I am the LORD thy God, which brought thee out of the land of Egypt,
from the house of bondage.
As for "works", notice, it is "works", and not "rest", which is that the Sabbath commandment is about. To break God's Law, is to still be in one's own "works", and not entered into the "rest" with God, whose "works" were "finished" "from the foundation of the world" (Genesis 2:1-3), in the 7th day. To break the Sabbath commandment is self-murder (Galatians 5:21), since it breaks down the body, mind and heart, for one was supposed to cease, but didn't and gave the body, mind and heart not the specified time to rest. It breaks all of the commandments, and is adultery, spending the time with another, doing ones own thing rather than what God required:
Isaiah 58:13 If thou turn away thy foot from the sabbath, from doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the LORD, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking thine own words:
Notice James again:
James 2:10 For whosoever shall
keep the whole law, and yet
offend in one point, he is
guilty of all.