Why could the Passover not have been on a Saturday?
The Passover required animal sacrifice, but the Sabbath was never a day of sacrifice in Israel. No record exists of Jews killing an animal on Saturday, because the Sabbath was a day of rest, not worship or ritual. A Saturday Passover would therefore contradict everything Scripture shows about Sabbath practice.
Les explains that the Sabbath day, Saturday, was not a day of sacrifice. Never in Israel's history did they sacrifice animals on the Sabbath; there is no record that they ever killed an animal on Saturday. The Sabbath was a day of rest, not a day of worship and sacrificing and ritual. They were not even to pick up sticks, let alone carry an animal up to have it sacrificed. Consequently, the Passover could not have been a Saturday Passover, because that would have flown in the face of everything that took place before.