I'll add just a bit or two, in the interest of gradualism...
Yeshua fulfilled the Spring feasts perfectly on His first coming (as "Meshiach ben Yosef, or Messiah, son of Joseph - the 'Suffering Servant'). Literally everything that He did, down to small details and with perfect timing, fulfilled what was Written concerning Pesach, or Passover. He was the Perfect Lamb (even the things said about Him, from "I find no fault in Him" to "It is finished" were ALL things that were traditionally said as the lamb was inspected, and as the final sacrifice was completed by the High Priest in the temple.) Even the Roman Centurion who saw the temple veil rent at the same time as he watched the Savior die "got it". Yeshua was "first fruits" of the dead, for us. He died on Wednesday afternoon, was in the tomb before sunset (which was the "dawning of the day" we call Thursday) and was risen at the end of the Sabbath, exactly 3 days and 3 nights later, as He had promised.
Everything about the traditional seder dinner speaks of Him. (Take a look at a Messianic haggadah service sometime, or watch
The Messiah with Nick Mancuso for a good introduction.) The matzah ("afikommen") is a great example - it is pierced and striped, broken, wrapped in a cloth, and hidden.
There's lots more, of course - but the wonder of DOING the service each year is that we get to study and SEE IT for ourselves.
The Fall Feasts are just as interesting (starting with Yom Teruah, the Day of Trumpets, where the only unique command is to sound a "shofar". Makes you wonder why He would want us to celebrate the ONLY feast which starts on a New Moon, and which is traditionally referred to as the feast of which "no man knows the hour of the day" for that reason, would involve something that starts with a trumpet.
(The Fall Feasts, I contend, are next - when He returns as Meshiach ben David, the King.)
We have ten days (the "days of Awe") to repent, clean up our act, and get ready for what follows; Yom Kippur, or the "Day of Atonement". Shortly thereafter (and just recently completed) are the eight days of Sukkot, or Tabernacles. This one has at least a double meaning - it commemorates the wandering in the wilderness (that which was, and that which is to come), and ends in the biggest feast or celebration on His calendar.
It is usually likened to a wedding feast. Wonder what that could symbolize?
Blessings,
Mark