Kiddush is to sanctify the Sabbath and holidays with a “special blessing” over wine.
Normally Kiddush is a home ceremony on Friday nights. Starting in the middle ages it was also said in the Synagogue during the Friday night service for visitors who had their meal adjacent to the Synagogue, as such it has become a custom on Friday nights at home and at the Synagogue. (Ref:1)
The Kiddush is a remembrance of the act of creation and on the sixth day the heavens and the earth and all that is in them was complete and on the seventh day God rested from all the labor which He had performed. And God blessed the seventh day and He sanctified it for on it He ceased from the labor he had been doing and rested. (Genesis 2:1—3)
Recite the blessing over the wine:
The Kiddush is a remembrance of the Sabbath day to keep it Holy and as a pattern for God’s people to be a people “set apart,” a people resting in Yeshua’s salvation, His redemption, His provision.
The Kiddush is said before each meal or snack on Shabbat. This is why we say the Kiddush before we start Oneg (refreshments) after the service each Erev Shabbat Friday night.
Luke 22:19-21 And when He had taken some bread and given thanks, He broke it and gave it to them, saying, “This is My body which is given for you; do this in remembrance of Me.” And in the same way He took the cup after they had eaten, saying, “This cup which is poured out for you is the new covenant in My blood. (NASU)
At a Passover Seder the cup after the meal is the “cup of redemption” this is the 3rd cup of the Seder and Yeshua was telling them this cup was being poured out for them. Redemption was at last physically initiated as it had been planned from the beginning of creation until now as it was manifest on the cross. Yeshua was reciting the Kiddush after the meal just as we do each Passover.
The Kiddush is a general prayer and a remembrance of God’s provision and sanctification, His setting aside a day for enjoying His rest, many Messianic believers cannot help but remember the perfect sacrifice provided by our L-RD in Yeshua and thinking about His words when He recited the Kiddush at the Passover.
Ref:1 http://www.myjewishlearning.com/practices/Ritual/Shabbat_The_Sabbath/At_Home/Kiddush.shtml