Kafka continues his letter to his father:Later, however, I came to look at Judaism differently and understood why you might believe I had maliciously betrayed you in that respect. You really brought a certain amount of Judaism from your small ghetto-like village community. It wasn’t much and lost a little more in the city and during your military service, but the youthful impressions and memories were enough for a kind of Jewish life style, especially since you didn’t need a great deal of help in that respect. You were made of solid stuff and could not be shaken by religious considerations if they weren’t mixed with social considerations. On the whole the faith that guided your life consisted in a belief in the absolute correctness of the opinions of a certain Jewish social class, and actually also in a belief in yourself, since those opinions were part of your own nature. There was enough Judaism in your nature, but too little to be handed on to a child. It seeped away and dried up as you handed it on. In a way those youthful impressions couldn’t be handed on. Either that, or your terrifying personality prevented it. It was impossible to impress on a child full of anxiety and therefore too closely observant that those few empty rites you practiced in the name of Judaism had any higher meaning, when you practiced them with an apathy corresponding to their emptiness. They were meaningful to you as small mementos of a bygone time and for that reason you wanted to hand them on to me, but you could not do it without urging and threatening me, since they had no intrinsic value for you. On one hand it was an undertaking that could not succeed, on the other hand you did not recognize your weak position in this matter and therefore were very angry with me on account of my apparent obstinacy… If your Judaism had been stronger, your example would have been more cogent.
(Source: Letter to my Father, text on www.kafka.org; my translation)