Rebbe Nachman of Breslov’s famous saying, מצווה גדולה להיות בשמחה (Mitzva gedola l’hyot b’simcha), “It’s a big mitzva to be happy”, is not necessarily an halachic opinion, but good life advice. However, (ושמחת בחגך (דברים ט״ז י״ד (V’Samachta b’Chagecha, Devarim 16:14), “And you will be happy on your festival”, does have the weight and status of a מצווה דאורייתא (Mitzva D’Oreita) Biblical commandment.
In contrast to Shabbat, where the concept of ענג שבת (Oneg Shabbat), Enjoying Shabbat, is a Rabbinic injunction and is based on a prophetic verse (Isaiah 58:13), וְקָרָאתָ לַשַּׁבָּת עֹנֶג (V’Karata l’Shabbat Oneg) “And you will call Shabbat a pleasure”, being happy on the חגים (Chaggim) Festivals is a profound Torah obligation.
I remember my rebbe, Rabbi BCSZ Twerski zt”l, saying that Simchat Yom Tov (שמחת יום טוב), was the “hardest mitzva in the book”. Turning on our joy and maintaining it for 48 hours (longer if one includes the intermediate days of Chol Hamoed), not allowing ourselves to become annoyed or angry or depressed, is a super-human task. He didn’t mean programmed “Happiness” of singing and dancing, but the actual inner feeling. The world, in its current mode, is just not that well-suited to sustained joy.
Even after we make the decision, using our בחירה (Bechira) Free Will, to be happy, we need every bit of סייעתא דשמיא (Si’ata d’Shemaya) God’s help that we can gather to be able to carry it out.
חג שמח וכשר (Chag Sameach v’Kasher), May you have a Joyful and Kosher Pesach.