Tosfos does not say that the Bnei Yisrael were forced into accepting the Torah, although they are often quoted as saying so. What Tosfos does in fact say, is that the holding of the mountain over the Bnei Yisrael was necessary in case they should decide to recant on their commitment. In fact, the Bnei Yisrael never said anything to suggest that they would not accept the Torah of their own free will, from which we may conclude that they did not in fact retract their original statement. The Gemara that states mi'Ka'an Moda'a Raba le'Oraysa, means that Bnei Yisrael could claim that they only accepted the Torah under duress and, therefore are not liable for their actions, since it is possible that had it not been for the coercion of the mountain, they may have chosen not to accept the Torah due to the Eish ha'Gedolah.

The question that is posed by the explanation offered by Tosfos, however, is why was the Eish ha'Gedolah necessary? Surely it would have been better for Hash-m not to show the Bnei Yisrael the Eish ha'Gedolah, and to thereby avoid the necessity for the Har k'Gigis? The answer is that Hash-m wanted to show the Bnei Yisrael that in accepting the Torah they were in fact accepting upon themselves the Eish ha'Gedaolah of Hash-m, which represents the retribution for those that do not keep the laws of the Torah. This information is obviously crucial for Matan Torah, because Hash-m would not give punishment to those who violate his words without informing them of the consequences of their actions first. However, the side effect of this course of action was that Bnei Yisrael may wish to reconsider their decision in light of the severity of the punishment. It was therefore necessary for the Har k'Gigis.

Others (see Maharal Shemos 19:17, Sfas Emes Shavuos 5633, Rav Dessler Michtav mei'Eliyahu vol. 2) suggest that when Hash-m came to give the Torah on Har Sinai he revealed himself in such a way that that the Bnei Yisrael had such a clear recognition of the true nature of the world that they had no Bechirah left to enable them to sin. This is what is represented by the Eish ha'Gedolah (Hash-m revealed his presence - see Targum to Shemos 19:20) and by the Har k'Gigis (the Jews were left with a lack of Bechirah). According to this Peshat, Bnei Yisrael still in fact could choose not to accept the Torah but they realized that to do so would mean that the world would no longer serve any purpose and would thus cease to exist. This is the Moda'a Raba, that Bnei Yisrael accepted the Torah in a state of great understanding and those not on that level cannot be held responsible for their deeds through the acceptance of their forefathers who were on a different level of understanding. According to this Peshat the Bnei Yisrael accepted the Torah of their own free will.

Dov Freedman