This was the day before the Sabbath, spent in "preparation" for this special Sabbath--the Sabbath of the Passover week. The Jews were scrupulous about allowing no work on the Sabbath, so it was necessary for the two friends to finish the burial necessities to the extent they could before the sun went down. Thus, just as the Lord rested one day after finishing the work of His creation week, so He would also rest another full day after finishing His redemption work.

Source:

KJV Defenders Study Bible, by Dr. Henry Morris, Ph.D.
Publisher: Thomas Nelson
Language: English
DEF 10 ISBN 0-529-10444-x
DEF 10-1 ISBN 0-529-10445-8