Gemara: Rav Yehuda became very sick and recovered. Rav Chana of Bagdad and the rabbis came to visit him and said (in Aramaic): "Blessed is the Merciful One who gave you to us and did not give you to the earth." [Rav Yehuda] said: You have exempted me from thanking [saying Birkat Hagomel]… How could it be, since [Rav Yehuda] was not the one who made the blessing? He answered "Amen."

Ein Ayah: For a great person in the realm of wisdom and ethics like Rav Yehuda, illness and the bitter possibility of his passing from the world did not relate primarily to him but to the people around him. A problem can arise when the great person’s associates do not sufficiently appreciate the value of the benefit they receive by having a person of his stature in their midst. In order to awaken them to this realization, Hashem may bring an illness, so that it will result in a fear of losing the great person.
That is why Rav Chana and the others expressed that the main thanksgiving should come from them for not having lost Rav Yehuda [as it was their response that Hashem was trying to elicit]. They purposely made the beracha of thanksgiving in a simple language which would have been more appropriate from a simple person. This signified that without a great scholar and tzaddik like Rav Yehuda and his spiritual impact upon them, they would sink to a much lower level. They wanted to hint that they would be unable to express themselves on a high level, such as speaking in Lashon Hakodesh (the Holy Tongue – Hebrew), which the angels use. Therefore, they gave their thanks in Aramaic, the coarse language of the masses [not normally used in reciting blessings] to indicate that the lowness of Aramaic is what they should expect of themselves without the presence of Rav Yehuda.
They also stressed in the beracha that "Hashem gave you to us," for their purposes and to elevate them and "not to the earth." This description of death also stresses the simplistic material element of the body returning to the earth and decaying, without getting into the more intellectual/spiritual outlook into death. This, again, indicated the feeling of inadequacy that those who blessed felt without Rav Yehuda. They also meant to hint that the waste of losing Rav Yehuda without having maximized the gain from his influence would be like an object that was covered up by the ground and lost. Now that they showed their recognition of what they should have done, they would be inspired to concentrate on learning as much Torah and ethics from him as they could.
Rav Yehuda expressed that he was aware of the need for a personal expression of thanks for his recovery from illness. However, since he already saw that there was a benefit that came from his illness in the realm of Torah and piety (to the others), he already was able to view the illness as something for which to be thankful. By answering Amen, he showed how, with an enthusiastic heart, he was happy with his physical pain since it was the source of blessing to many. As far as his own feelings were concerned, "the cow wants to give its milk more than the calf wants to receive it" (i.e., the teacher wants his students to learn more than they do).