There was none of today's "ham and shrimps are forbidden to Orthodox Jews." All Jews, no matter what their personal belief and "life style" accepted G-d's Commandments.
Just as I was checking my email tonight I saw the Tablet Magazine headlines which includes:
An Atheist for ReligionAnd I thought of our all Jewish souls, even those not yet born, being at Mount Sinai meant that even the atheists among us called out:
In Religion for Atheists, Alain de Botton urges nonbelievers to pick and choose religions’ best offerings
נעשה ונשמה Na'aseh v'Nishma, We Will Do and We Will Listen
Yes, that means that the non-believers among us, aka the atheists were there, too. We all promised, pledged to obey G-d on that original Shavuot, which is usually translated as "weeks," although the letters spelled the same way also mean "oaths." The Holiday of Shavuot is the culmination of the seven week count up from the beginning of Passover until the end of seven (also spelled with the same Hebrew root שבע shevva) weeks which is the Eve of Shavuot.
We did not promise to always believe and understand all that G-d wants from us. We had just pledged to obey G-d's Commandments, no questions asked.
I have no doubt that not all of the Jewish people who escaped together from slavery to Pharaoh in Egypt were strong believers in G-d. Actually, the more I study the less they seem to have had been of strong faith in G-d. Think of all their complaints just a short time after leaving Egypt and experiencing so many miracles. They missed the food and the security and lack of responsibility. There are advantages to slavery. You may not get much pay, but the food and housing are free.
We've been discussing that issue, the difficulties and burdens of freedom in the Matan class I've been taking, Change of Course and Course of Change: Sefer B´Midbar taught by Atara Snowbell.
In a sense we must sympathize with the former slaves. They really weren't prepared for their new lives. Maybe some of them thought that if they promised G-d they'd obey, He would give them on tap food, like they remembered getting in Egypt. Yes, no doubt in my mind that there were atheists among them.