In the Hebrew the word day is described as the "warm hours". One thing one should never do. Go to those who hate Christ to find out how to be a good Christian. Those who hate Christ start their time with darkness (sun setting below the horizon) and death. God's way is light and life. We can not follow God's calendar today, unless one is financially independent. The day changes every year because it is counted from the first day of Spring.We do the best we can. The only way I could make sense of "and the evening and the morning" is to start the day at noon. So I do a Sabbath from about noon Saturday for 24 hours. People who work or have commitments might have to do all day Sunday or Monday for example. Some day all God's way will be restored.