What is the reason & significance of concluding the Pesach seder with the singing of "Le`shanah ha ba`ah be yerushalayim " Where and when did this custom originate ?

Throughout the whole Seder we are supposed to feel as if we left Egypt and experienced the exodus ourselves. This is done every generation. There is one higher step we wish to reach and we hope and pray for and that is to be able to keep the Chag in its complete form with the great festivity in the Beit Hamikdash with The Pesach sacrifice. We wish all the Hagadah to receive a more practical aspect as we say “and we shall eat there from the Zevachim (offerings) and from the Pesachim (Pesach offerings)”. This is also the reason for the announcement at the end of the evening: Next Year in Jerusalem. Rabbi Ro’I Margalit