Esto es en respuesta a LuisAlberto42 (para no ocupar una pagina entera con la cita)
El commentario de Matthew Henry dice acerca de Apocalipsis 1

3. The day and time in which he had this vision: it was the Lord's day, the day which Christ had separated and set apart for himself, as the eucharist is called the Lord's supper. Surely this can be no other than the Christian sabbath, the first day of the week, to be observed in remembrance of the resurrection of Christ. Let us who call him our Lord honour him on his own day, the day which the Lord hath made and in which we ought to rejoice.
Albert Barnes Notes on the Bible:
On the Lord’s day - The word rendered here as “Lord’s” (κυριακῇ kuriakē), occurs only in this place and in 1Co_11:20, where it is applied to the Lord’s supper. It properly means “pertaining to the Lord”; and, so far as this word is concerned, it might mean a day “pertaining to the Lord,” in any sense, or for any reason; either because he claimed it as his own, and had set it apart for his own service, or because it was designed to commemorate some important event pertaining to him, or because it was observed in honor of him. It is clear:
(1) That this refers to some day which was distinguished from all other days of the week, and which would be sufficiently designated by the use of this term.
(2) that it was a day which was for some reason regarded as especially a day of the Lord, or especially devoted to him.
(3) it would further appear that this was a day particularly devoted to the Lord Jesus; for:
(a) that is the natural meaning of the word “Lord” as used in the New Testament (compare the notes on Act_1:24); and
(b) if the Jewish Sabbath were intended to be designated, the word “Sabbath” would have been used.
The term was used generally by the early Christians to denote the first day of the week. It occurs twice in the Epistle of Ignatius to the Magnesians (about 101 a.d.), who calls the Lord’s day “the queen and prince of all days.” Chrysostom (on Ps. 119) says, “It was called the Lord’s day because the Lord rose from the dead on that day.” Later fathers make a marked distinction between the “Sabbath” and the “Lord’s day”; meaning by the former the Jewish “Sabbath,” or the seventh day of the week, and by the latter the first day of the week, kept holy by Christians. So Theodoret (Fab. Haeret. ii. 1), speaking of the Ebionites, says, “They keep the Sabbath according to the Jewish law, and sanctify the Lord’s day in like manner as we do” (Prof. Stuart). The strong probability is, that the name was given to this day in honor of the Lord Jesus, and because he rose on that day from the dead. No one can doubt that it was an appellation given to the first day of the week; and the passage, therefore, proves:
(1) that that day was thus early distinguished in some special manner, so that the mere mention of it would be sufficient to identify it in the minds of those to whom the apostle wrote;
(2) that it was in some sense regarded as devoted to the Lord Jesus, or was designed in some way to commemorate what he had done; and,
(3) that if this book were written by the apostle John, the observance of that day has the apostolic sanction. He had manifestly, in accordance with a prevailing custom, set apart this day in honor of the Lord Jesus. Though alone, he was engaged on that day in acts of devotion. Though far away from the sanctuary, he enjoyed what all Christians hope to enjoy on such a day of rest, and what not a few do in fact enjoy in its observance. We may remark, in view of this statement:
(a) that when away from the sanctuary, and deprived of its privileges, we should nevertheless not fail to observe the Christian Sabbath. If on a bed of sickness, if in a land of strangers, if on the deep, if in a foreign clime, if on a lonely island, as John was, where we have none of the advantages of public worship, we should yet honor the Sabbath. We should worship God alone, if we have none to unite with us; we should show to those around us, if we are with strangers, by our dress and our conversation, by a serious and devent manner, by abstinence from labor, and by a resting from travel, that we devoutly regard this day as set apart for God.
(b) We may expect, in such circumstances, and with such a devout observance of the day, that God will meet with us and bless us. It was on a lonely island, far away from the sanctuary and from the society of Christian friends, that the Saviour met “the beloved disciple,” and we may trust it will be so with us. For on such a desert island, in a lonely forest, on the deep, or amid strangers in a foreign land, he can as easily meet us as in the sanctuary where we have been accustomed to worship, and when surrounded by all the privileges of a Christian land. No man, at home or abroad, among friends or strangers, enjoying the privileges of the sanctuary, or deprived of those privileges, ever kept the Christian Sabbath in a devout manner without profit to his own soul; and, when deprived of the privileges of public worship, the visitations of the Saviour to the soul may be more than a compensation for all our privations. Who would not be willing to be banished to a lonely island like Patmos, if he might enjoy such a glorious vision of the Redeemer as John was favored with there?
Adam Clarke's commentary on the Bible:
The Lord’s day - The first day of the week, observed as the Christian Sabbath, because on it Jesus Christ rose from the dead; therefore it was called the Lord’s day, and has taken place of the Jewish Sabbath throughout the Christian world.
Jamieson, Fausset and Brown Commentary:
on the Lord’s day — Though forcibly detained from Church communion with the brethren in the sanctuary on the Lord’s day, the weekly commemoration of the resurrection, John was holding spiritual communion with them. This is the earliest mention of the term, “the Lord’s day.” But the consecration of the day to worship, almsgiving, and the Lord’s Supper, is implied in Act_20:7; 1Co_16:2; compare Joh_20:19-26. The name corresponds to “the Lord’s Supper,” 1Co_11:20. Ignatius seems to allude to “the Lord’s day” [Epistle to the Magnesians, 9], and Irenaeus [Quaest ad Orthod., 115] (in Justin Martyr). Justin Martyr [Apology, 2.98], etc., “On Sunday we all hold our joint meeting; for the first day is that on which God, having removed darkness and chaos, made the world, and Jesus Christ our Savior rose from the dead. On the day before Saturday they crucified Him; and on the day after Saturday, which is Sunday, having appeared to His apostles and disciples, He taught these things.” To the Lord’s day Pliny doubtless refers [Epistles, Book X., p. 97], “The Christians on a fixed day before dawn meet and sing a hymn to Christ as God,” etc. Tertullian [The Chaplet, 3], “On the Lord’s day we deem it wrong to fast.” Melito, bishop of Sardis (second century), wrote a book on the Lord’s day [Eusebius 4.26]. Also, Dionysius of Corinth, in Eusebius [Ecclesiastical History, 4.23, 8]. Clement of Alexandria [Miscellanies, 5. and 7.12]; Origen [Against Celsus, 8. 22]. The theory that the day of Christ’s second coming is meant, is untenable. “The day of the Lord” is different in the Greek from “the Lord’s (an adjective) day,” which latter in the ancient Church always designates our Sunday, though it is not impossible that the two shall coincide (at least in some parts of the earth), whence a tradition is mentioned in Jerome [Commentary on Matthew, 25], that the Lord’s coming was expected especially on the Paschal Lord’s day. The visions of the Apocalypse, the seals, trumpets, and vials, etc., are grouped in sevens, and naturally begin on the first day of the seven, the birthday of the Church, whose future they set forth [Wordsworth].
Todos dicen lo mismo el día del Señor del cual Juan habla es un Domingo.
El día del Señor de Pedro es otra cosa.