The Feria (Roots of Sunday Worship)

"A feria (Latin for "free day") was a day on which the people, especially the slaves, were not obliged to work, and on which there were no court sessions." Wikipedia

"Rabanus Maurus (776-856), abbot of Fulda and later archbishop of Mainz, Germany, was rated one of the greatest theologians of his age and probably the most cultured man of his time, and exceptionally learned in patristics. Besides, he was a zealous defender of the papacy and its teachings. In one of his works, he says,

"Pope Sylvester instructed the clergy to keep the feriae. And, indeed, from an old custom he called the first day [of the week] the "Lord's [day]," on which the light was made in the beginning and also the resurrection of Christ is celebrated.

Pope Sylvester first among the Romans ordered that the names of the days [of the week], which they previously called after the name of their gods, that is, [the day] of the Sun, [the day] of the Moon,

[the day] of Mars, [the day] of Mercury, [the day] of Jupiter, [the day] of Venus, [the day] of Saturn, they should call feriae thereafter, that is the first feria, the second feria, the third feria, the fourth feria, the fifth feria, the sixth feria, because that in the beginning of Genesis it is written that God said concerning each day: on the first, "Let there be light:; on the second, "Let there be a firmament"; on the third, "Let the earth bring forth verdure"; etc. But he [Sylvester] ordered [them] to call the Sabbath by the ancient term of the law, [to call] the first feria the "Lord's day," because on it the Lord rose [from the dead], Moreover, the same pope decreed that the rest of the Sabbath should be transferred rather to the Lord's day [Sunday], in order that on that day we should rest from worldly works for the praise of God."

But when is God's Feria-

Six days shalt thou labour, and do all thy work: But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work,

Exodus 20:9,10

Bede, the noted English monk and ecclesiastical writer (672-735 A.D.), ....says -

"Question: Who first taught to observe feriae? Answer: Pope Sylvester instructed the clergy to observe feriae, to whom, resting only to God, it was allowed to engage in no military service or worldly business. ... And indeed because light in the beginning was made on the first day, and the resurrection of  Christ [being] celebrated [on it], he called [it] the Lord's [day].' "

A contemporary of Emperor Constantine and Pope Sylvester I., was Eusebius Pamphili 260-341 A.D., Bishop of Cæsarea in Palestine. About 330 A.D. he wrote:

... "and all things whatsoever that it was duty to do on the Sabbath, these we have transferred to the Lord's day, as more appropriately belonging to it, because it has precedence, and is first in rank, and more honorable than the Jewish Sabbath."  (Reminder inserted here about the Little Horn power-- And he shall speak great words against the most High, .. and think to change times and laws: Daniel 7:25)

So do we honor the Feria of God 
on Sabbath (7th day) 

or on Sunday (1st day)?

Peter says - We ought to obey God rather than men. Acts 5:29