John Gill Commentary Mark 15:42

"And when even was now come, because it was the Preparation, that is, the day before the sabbath," — Mark 15:42 (ASV)

And now when the even was come
"Of the preparation", as the Syriac version reads; or "the night of the sixth day":, as the Persic version renders it, "Friday" night:

because it was the preparation ;
of the passover, and of the sabbath, when they prepared their food, and got it ready for the ensuing sabbath, on which it was not lawful to dress any;

that is, the day before the sabbath ;
that is, Friday; on which day, it is clear, Christ suffered, died, and was buried.