2) All Church commandments are in force as earlier;

3) Comprehending G-d’s Commandment of the Rest of the 7^th Day (Sabbath) as Y-shua‘s Rest in Grave on Sabbath between His Death and Resurrection, Messianic believer is obliged to keep the Sabbath of G-d, what is the first and the main of all celebrations ordained in Torah. Sabbath is celebrated from the sunset on Friday evening till 50 min. after the sunset on Saturday evening.

Messiah Y-shua‘ rigorously refuted all human-invented novations assigned to Sabbath by post-Babilonic rabbinic tradition. By contrast, He confirmed the eternity of Sabbath in coming days of Redemption in Mt 24,20, because this is namely Him Who has revealed the prophetic sense of Sabbath for Himself when He fulfilled Gen 2,2 with His Divine Rest in Grave after His Atoning Sacrifice before the Resurrection!

Sabbath was strictly kept by Apostle Paul and the first pupils of Y-shua‘ (Acts). The importance of Sabbath (sabbatismus) has been confirmed for the whole G-d’s people, of the past and of the future, in Hebrews 4,9, not only in Decalogue!

One seventh of the life of every true believer shoud be dedicated to G-d only!

To keep the Sabbath means:

The Sabbath is an allusion of G-d to the Rest (Gen 2:2) of His incarnation (Isaiah 40:28) after all His works and preaching between His Death and Resurrection. Then the Day of Resurrection follows, which is the first day of the week according to original Jewish-Aramaic → Greek order of days of the week.  

4) Every Messianic believer is obliged to celebrate on Sunday (the first day of the week, what is one of the Church commandments in turn) the Resurrection of our L-rd Messiah Y-shua‘ after His Sabbathic Rest in Grave. The Day of His Resurrection also means the Eighth Day of the final Re-Creating the word eschatologically as One Everlasting Sabbath in G-d, the aim of the Salvation. Therefore the first day of the week becomes the eighth one as an eschatological fulfilment of the first day of Creation. 
Although not being a Bible feast, the First-Eighth day of the week is timeless, not a calendar one. Messianic weekly celebration of the first day of the week during community meetings corresponds to traditional Christian Easter feast.

To celebrate Resurrection of Messiah means to messianically continue celebration of the Sabbath, that is:

to participate in the Eucharist (Acts 20,7),
not to do any dirty work at home, not to do any work for money.
The Sabbath Rest already kept (its requirements having expired after the Eucharist), one may buy food and requisites in shops and markets if necessary.

RECOMMENDED:
Any charitable work without material reward including dirty household works (provided the recepient has sane conscience about this dirty work to be done on Sunday).

Thus celebration of the first day of the week does not negate celebration of the seventh day of the week, and vice versa. It is Messianic Judaism only which is capable to unite both days into one Festival of both Covenants!  
Therefore, it inspires hope to overcome both the Laodicean prohibition of celebrating Sabbath in 364, as well as Adventists’ criticism of Sunday as a pagan “day of the Sun“ allegedly introduced by Constantin “instead of Sabbath” (as erroneously said by many of them).

A sort of overcoming both extremities could be attained by identifying the Havdalah (“separation of the holy and laic time”) with the hour after the Sunday Eucharist. When performed at night after the sunset of Sabbath, the Eucharist  brings Havdalah back to apostolic times. Such joinder of Covenants would disembarass traditional Christians from theological “creative torments” unluckly violating text of the Decalogue with shifting “Saturday” fo “Sunday”. 
Messianic Jews should not be frightened to partly transgress the Rabbinic tradition by broadening the sense of the Havdalah, because only to recognize Y-shua‘ as Messiah seems to be the greatest of all possible transgressions for this tradition;

5) Having joined the Messianic Jewish movement, the traditional Nicene Christians should keep celebrating their Church festivals side by side with celebration of the Torah-established and in the Tanakh mentioned Jewish holidays according to the Jewish calendar:

Pesah on Nisan 14/15  A Torah feast and „Great Thursday” Messianic feast of establishing the Eucharist during the Last Supper, when the remembrance of the Passover sacrificial lambs with their blood on door posts of Jewish houses (Exodus 12,7) was converted into remembrance of the eternal Lamb and His Redemptive Blood, but the remembrance of Exodus from the slavery in Egypt was broadened as exodus from the slavery of sin.
This feast in any way is a feast of Messiah's Resurrection happened on Nisan 16. No one messianic community celebrates Nisan 16 as a New Covenant feast of Resurrection! Traditional Jewish Pesach corresponds to the Feats of Eucharist in Traditional Christianity.

Shavu‘ot on Sivan 6-7, WEEKS (7) after Pesah  A Torah and Messianic Pentecost feast confirming the fulfilment of Pesah by first fruits of the Promised Land. This feast (always on Sunday according to the Book of Jubilees) at the same time is the Feast of Y-shua‘ Resurrection (traditional Easter! ), as well as the feast of coming of the Holy Spirit to the Church,

Yom Teruah on Tishri 1 , the Day of Trumpets, is known as Jewish New Year, Rosh Ha-Shanah, introduced from a pagan Babylonic feast together with Babylonic calendar and its month of a pagan deity Tammuz. Comprehending history as a struggle between Monotheism and Idolatry, the meaning of Yom Teruah is seen in falling walls of Pagan Jericho: it is a feast of the final destruction of the world heathendom when the King of Israel Messiah Y-shua‘ comes to judge.

Yom Kippur on Tishri 10 A Torah Day of redemptive Reconciliation between Israel and G-d through substitutional sacrifice, what allows Messianic believers to keep it as Remembrance the Substitutional Sacrifice of Messiah, cf. Isaiah 53, i.e. as the Holy Great Friday of traditional Christianity (Messianic time is not heathenish cyclical, but it is spiritually linear, finally separated from natural cyclic time). Yom Kippur is special time for repentance, renouncement of sinning and light-minded personal oaths.
Strict fasting recommended!

Sukkot on Tishri 15-22 ending with Simhat Torah on Tishri 22 A Torah feast of Tabernacles, Messianic feast of restoring G-d’s Tent in human souls (Mathew 17,4); ends with celebration of finishing and beginning of annual reading of Torah and Gospel,

Hanukkah on Kislev 25 [2 Maccabees 10,5-8] feast of Purifying the Temple – feast of Gd’s Light: a Messianic feast of coming of the Light of Truth into the world [Malachi 4, 2 (3:20)], an authentic Christmas of the first Jewish Christians (celebration of birthdays was a heathen feature, only Temple festivals were celebrated by faithful Jews),

Purim on Adar 14-15 [Esther 9,27-28] is not a Torah-feast and is not obligatory for Messianic believers. However it may be celebrated together with all Jews as a feast of reliance upon G-d who redeems His people from any hopeless disaster.

6) Similarly to the feasts, all traditional Christian fasts are kept in own churches as earlier in accordance with Church commandments, however Jewish fasts (as that of the 9^th of Av) are kept at own discretion;

7) The beginning of every Jewish month should be hallowed by lighting candles with a corresponding prayer on the sunset of the last day of the previous month;

8) In accordance with G-d’s statutes, one should shy away from leavened or possibly leavened food during the whole week of the unleavened bread. Strictly kasher food is not obligatory (particularly while it is considered obligatory to be prepared and distributed by the Halacha Jews only), however one should not eat pork or food containing pork anyway. This is an exclusive feature of the Abrahamic faith (Judaic or Moslem), ordained by G-d and differentiating an Abrahamite from all the pagans (not to say that pork is unhealthy);

9) One should confess as a sin any breach of whatever own commitment undertook by joining the Messianic movement;

10) Christian men of the Jewish origin, or of gentile origin when they wish to belong to the Jewish people physically and perform circumcision at a Messianic or a Halachah rabbi, should keep all keepable commandments of Torah additionally during all their remaining life (Galatians 30,3 and Acts 16,3, cf. also Acts 21,26), as this is done in families of traditional orthodox Jews. Nevertheless rules of the kasher food should not constrict realtions between the Messianic Jews and those Christians of the gentile origin who have joined the Messianic movement. It is not reprehensible to get kasher matzos or wine from the Halachah Jews anyway. However it would be unethical to intercept rules of kasher kitchen utensils because such rules are absent in Torah, they are useless for Salvation and only create a partition between Messianic Jews and Christians of the gentile origin;

11) Halachah rules are not obligatory in any case. However one is welcome to take interest in them in order to perform Messianic commitments in the best way and to have affinity of behavior with those Messianic Jews who have grown up in Jewish traditions;

12) On the one hand, traditional Christians of the gentile origin, who join the Messianic movement, should comprehend how unacceptable is hallowing of symbols and images (as icons or statues) for all Jews (the Decalogue was proclaimed namely for them at the Mount of Sinai), however on the other hand, such Christians should avoid folk veneration of images or statues, as only possible, in spite of elevating the human nature on Divine level by the Incarnation of Y-shua‘ what has enable at least Christians of the gentile origin to have images and photos of people starting from Y-shua‘ Himself.

Having joined the Messianic movement, Chrisians of the gentile origin should celebrate Jewish feasts praying with reverentially covered head (men with a kipa, women with a shawl or with own hairs covering ears). Paul’s notes in 1 Corinthians 11, 4-5, are addressed to gentiles, although also prescribe women to show meekness by covering their heads (ibid. 5-6, and 1 Timothy 2,11), however praying of men with an uncovered head can be comprehended as a sign of liberation of Jewish rules, not to mention random inconsistencies of Paul himself (cf. 2 Peter 3,16).