To begin it is important to establish that Saturday is indeed the Sabbath.
In addition to this fact, many Christians go to church on Sunday.
The immediate follow-up question to knowing these facts is why Christians go to church on Sundays and not Saturdays.
8 “Remember the Sabbath day by keeping it holy. 9 Six days you shall labor and do all your work, 10 but the seventh day is a sabbath to the Lord your God. On it you shall not do any work, neither you, nor your son or daughter, nor your male or female servant, nor your animals, nor any foreigner residing in your towns. 11 For in six days the Lord made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day. Therefore the Lord blessed the Sabbath day and made it holy.
Exodus 20:8-11(NIV)
In this referenced passage from Exodus, you can clearly see God’s instructions on how we should handle our week. Indicating that we do our work every other day and then keep the Sabbath as a holy day in reverence to him. However, let me point you to a passage created later down the Biblical timeline.
On the first day of the week we came together to break bread.
Acts 20:7(NIV)
It is understood in the Bible that Sunday is the first day of the week and Saturday is the last day. This statement was incited by Paul post the resurrection of Jesus.
On the first day of every week, each one of you should set aside a sum of money in keeping with your income, saving it up, so that when I come no collections will have to be made.
1 Corinthians 16:2(NIV)
I am not sharing these passages with you to convince you that Sunday is the right day to do things for the Lord. In fact, it should be any day of the week, regardless of time or hour. Worshipping God in communion with your brothers and sisters is and will always be a good thing. The prime reason that many Christian churches hold their services on a Sunday is that Jesus was resurrected on the first day of the week.
With that being said, it is completely fine to rest in the Lord on a Sunday, in truth we should aim to make time for such action every day of the week.