>> Seems to me that some verses speak of either
a whole day... 24 hours, or
the night part... 12 hours, or
the day part...12 hours when it refers to night and day. <<
Correct, just as in English, the word "day" in Scriptures can refer to either:
#1 A calendar date, consisting of 24 hours, <b>sunrise to sunrise</b>
#2 The sunlight portion of the day, which is 12 hours, <b>sunrise to sunset</b>
Neither of these is "sunset to sunset".
Examples of #1, the 24 hour day, are:
Genesis 7.24 And the waters prevailed upon the earth an hundred and fifty <b>days</b>.
Genesis 17.12 And he that is eight <b>days</b> old shall be circumcised among you
Examples of #2, a 12 hour day, showing that the "day is light", and the "night is dark" are:
Genesis 1.4 And God saw the light, that it was good: and God divided the light from the darkness. 1.5 And God <b>called the light Day</b>, and the <b>darkness he called Night</b>.
John 11.9 Jesus answered, Are there not <b>twelve hours in the day</b>? If any man walk in <b>the day</b>, he stumbleth not, because he seeth <b>the light</b> of this world. 11.10 But if a man walk in <b>the night</b>, he stumbleth, because there is <b>no light</b> in him.
A "work day" is 12 hours long. <b>A "rest day" is the same length: 12 hours.</b> The "night" is not associated with "work".
John 9.4 I must work the <b>works</b> of him that sent me, <b>while it is day</b>: the <b>night</b> cometh, when <b>no man can work</b>.
>> The Bible never contradicts itself--it does contradict man-made theology. <<
Exactly. And the man-made traditions it contradicts are the following:
Rabbinic <b>tradition #1</b>: "the Sabbath is 24 hours long"
Rabbinic <b>tradition #2</b>: a "day" is from "evening to evening"
Correct Bible truth: "The Sabbath begins at sunrise, is 12 hours long, and ends at sunset."
Here is <b>proof</b> that the Sabbath <b>starts in the morning</b>.
And it came to pass, that on the sixth day they gathered twice as much bread, two omers for one man: and all the rulers of the congregation came and told Moses. 16.23 And he said unto them, This is that which the LORD hath said, <b>To morrow is the</b> rest of the <b>holy sabbath</b> unto the LORD: bake that which ye will bake <b>to day</b>, and seethe that ye will seethe; and that which remaineth over lay up for you to be kept <b>until the morning</b>. 16.24 And they laid it up <b>till the morning</b>, as Moses bade: and it did not stink, neither was there any worm therein. 16.25 And Moses said, Eat that <b>to day; for to day is a sabbath</b> unto the LORD: to day ye shall not find it in the field. 16.26 Six days ye shall gather it; but on the seventh day, which is the sabbath, in it there shall be none. 16.27 And it came to pass, that there went out some of the people on the seventh day for to gather, and they found none.
Here is <b>proof</b> that the Sabbath <b>ends at evening</b>. This story takes place on the Sabbath. The people bring the sick to be healed when the Sabbath had ended, at sunset, also called "at even". Here it in from 3 different Gospel writers:
1.21 And they went into Capernaum; and straightway <b>on the sabbath day he entered into the synagogue</b>, and taught. ... 1.29 And forthwith, <b>when they were come out of the synagogue</b>, they entered into the house of Simon and Andrew, with James and John. 1.30 But Simon's wife's mother lay sick of a fever ... 1.31 And he came and took her by the hand, and lifted her up ... 1.32 And <b>at even, when the sun did set</b>, they brought unto him all that were diseased, and them that were possessed with devils.
4.38 And he arose out of the synagogue, and entered into Simon's house. And Simon's wife's mother was taken with a great fever ... 4.39 And he ... rebuked the fever ...
4.40 Now <b>when the sun was setting</b>, all they that had any sick with divers diseases brought them unto him; and he laid his hands on every one of them, and healed them.
8.14 And when Jesus was come into Peter's house, he saw his wife's mother laid, and sick of a fever. 8.15 And he touched her hand, and the fever left her: and she arose, and ministered unto them. 8.16 <b>When the even was come</b>, they brought unto him many that were possessed with devils: and he cast out the spirits with his word, and healed all that were sick
Now, look at some more details in the Genesis chapter 1 account. Notice carefully the progression in the story; we will use day 6 as an example:
23 And the evening
and the morning were the fifth day.
24 And God said, Let the earth bring forth...
26 And God said, Let us make man in our image,
27 So God created man ... male
28 And God blessed them,
29 And God said, Behold, I have given you every herb bearing seed
31 And God saw … and, behold, it was very good.
And the evening
and the morning were the sixth day
2:1 Thus the heavens and the earth were finished
2:2 And on the seventh day God ended his work … and he rested on the seventh day
3 And God blessed the seventh day and sanctified it
Notice the progression for day 6:
First, he says "Let the earth bring forth ...",
<b>And then</b> he creates the male
<b>And then</b> he creates the female
<b>And then</b> he blessed them
<b>And then</b> he told them what to eat
<b>And then</b> he saw it was good
<b>And then</b> evening
In the progression, the events are in order. "Evening" follows the Creator telling the couple what to eat. <b>By the time "evening" is mentioned, the work of that day is finished.</b>
What about the word "morning"? There can be two explanations that harmonize with the rest of Scripture.
#1 The word translated "and", Strongs Hebrew #1961, is more properly translated "followed":
"evening <b>followed</b> [#1961] the morning". For extensive word study, see:http://www.thecreatorscalendar.com/Articles/Word_Studies/Genesis_1_1-5.html
#2 The morning refered to is the pre-sunrise dawn, right before the new day begins. So after the day's work is done, then it is evening, then thru the night, the right before sunrise. The next new day begins at sunrise. That view is presented here: http://world-calendar.info/passionweek.htm
Conclusion: The Bible does not support a traditional "sunrise to sunrise" day, nor a "24 hour Sabbath": The Sabbath begins at sunrise, is 12 hours long, and ends at sunset.