Answer:

Christians offer prayers on Sunday. Sunday is considered the holy day for Christians and is often referred to as the Sabbath. It is the day when Christians gather together to worship, pray, and celebrate their faith.

Significance of Sunday:
Sunday holds great significance in Christianity for several reasons:

1. Resurrection of Jesus: According to Christian belief, Jesus Christ rose from the dead on a Sunday, which is known as Easter Sunday. This event is the cornerstone of the Christian faith and is commemorated every Sunday as a reminder of Christ's victory over death.

2. Day of Worship: Sunday is considered the day of worship for Christians. It is a time for believers to come together as a community and participate in various religious activities such as attending church services, listening to sermons, singing hymns, and offering prayers collectively.

3. Rest and Reflection: Sunday is often seen as a day of rest and reflection in Christian tradition. It is a time to pause from the busyness of everyday life, to reflect on one's faith and relationship with God, and to seek spiritual renewal.

4. Biblical Reference: The practice of observing Sunday as the day of worship can be traced back to the early Christian Church. In the New Testament, the Book of Acts mentions that the early believers gathered together on the first day of the week, which is Sunday, to break bread and pray.

5. Christian Tradition: Sunday has been recognized as the day of worship by various Christian denominations across the world for centuries. It is a day when believers can come together to strengthen their faith, support one another, and offer prayers collectively.

In conclusion, Sunday is the day of the week when Christians offer prayers. It holds great significance in Christianity as the day of worship, reflection, and communal gathering for believers.