Christian liturgy is a pattern for worship used (whether recommended or prescribed) by a Christian congregation or denomination on a regular basis. The term liturgy comes from Greek and means "public work". Within Christianity, liturgies descending from the same region, denomination, or culture are described as ritual families.
The majority of Christian denominations hold church services on the Lord's Day (with many offering Sunday morning and Sunday evening services); a number of traditions have mid-week Wednesday evening services as well. In some Christian denominations, liturgies are held daily, with these including those in which the canonical hours are prayed, as well as the offering of the Eucharistic liturgies such as Mass, among other forms of worship. In addition to this, many Christians attend services of worship on holy days such as Christmas, Ash Wednesday, Good Friday, Ascension Thursday, among others depending on the Christian denomination.
In most Christian traditions, liturgies are presided over by clergy wherever possible.
The holding of church services pertains to the observance of the Lord's Day in Christianity. The Bible has a precedent for a pattern of morning and evening worship that has given rise to Sunday morning and Sunday evening services of worship held in the churches of many Christian denominations today, a "structure to help families sanctify the Lord’s Day." In and , "God commanded the daily offerings in the tabernacle to be made once in the morning and then again at twilight". In Psalm 92, which is a prayer concerning the observance of the Sabbath, the prophet David writes "It is good to give thanks to the Lord, to sing praises to your name, O Most High; to declare your steadfast love in the morning, and your faithfulness by night" (cf. ). Church father Eusebius of Caesarea thus declared: "For it is surely no small sign of God’s power that throughout the whole world in the churches of God at the morning rising of the sun and at the evening hours, hymns, praises, and truly divine delights are offered to God.