There is a perennial question about Passover, and if people would stop looking at the Jewish calendars then there should be no question at all. The Hebrew calendar was an agrarian calendar. It did not change from year to year, as the Jews change their calendar according to the phases of the moon. But the Jews were never farmers, and neither are they Hebrews or Israelites. The Roman Catholic date for Easter over the past hundred years, based on the Jewish calendar, has been as early as March 23rd, and as late as April 25th. But the Hebrew calendar is organized around planting and the first fruits of crops, and the harvest time of Tabernacles. Therefore it could not swing back and forth from year to year, because in that manner it would never have been possible for the Hebrew society to be synchronized with the natural phases of agriculture.
The Hebrew year began each year at the Vernal, or Spring Equinox, and Passover was always 14 days from the day of the Equinox. The sabbath-week cycle began anew each year so that the Passover was always on the second Sabbath of the new year. This is how it should be calculated every year, without exception. Because the Spring Equinox on our modern calendar occurs on March 20th each year, then the Passover should begin on April 2nd each year. So the Hebrew sabbaths this year are on Mondays. Next year they will be on a different day. This solar calendar is not explicitly explained in any one place in Scripture in this manner, but it is indeed fully evident in the information that we are given, once we realize that the feasts must have been synchronized with the agricultural life of the ancient Hebrews.
In this manner, when the Pentecost, or Feast of First Fruits arrived 7 weeks after Passover, there would have been first fruits of the crops to offer to Yahweh. If the date had swung by as much as a month one way or another, the first fruits would either not be ripe, or they would be rotting in the fields and people would not be able to eat, as the first fruits are for God and they would have to await the feast. So if you must celebrate Passover on the "right" date, it is quite apparent that Passover should be celebrated each year beginning with the evening of April 2nd.
On the other hand, today we no longer sacrifice to God in the ancient manner. Christ is our Passover. And if you cannot take off from work every Monday, the Spirit of the law matters more than the letter of the law, and perhaps you can designate another day for a Sabbath. There have been various pretenders who have criticized our position on this, and they would rather cling to the myths of the Jews. Many people suppose that the Hebrews had a fixed 7-day week cycle which lasted indefinitely across the years, but that is simply not true. It is obvious in the Gospel that the apostles and the Judaeans had separate days for Passover, and were evidently using two different calendars.
But for the larger segment of society, a calendar only works when the entire society is in agreement. Most people cannot tell their employers that they need every Monday off this year, or every Tuesday next year. So Paul of Tarsus told the Romans that “5 One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind.” Then he instructed the Colossians to “16 Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days: 17 Which are a shadow of things to come; but the body is of Christ.” Rituals do not please Yahweh, but rather, a loving care for our brethren and keeping the spirit of His law, that pleases Yahweh.