Pesachim 34

 
Much of today’s daf (Pesachim 34) discusses the halachic principle of היסח הדעת (i.e. diverting or ceasing to focus one’s attention on a specific matter), and specifically, the necessity, as learnt from Bemidbar 18:8, to safeguard terumah and be attentive that it not be ‘contaminated’ by טומאה (impurity).
In general, wherever the principle of היסח הדעת is invoked by our Sages (eg. having washed our hands before a meal), it is because there is a practice, a concept, or an object that we are expected to guard, protect, or focus our undivided attention.
With this in mind, I’d like to mention the significance of today – the 10th of Tevet – on which we fast in order to remember the siege of Jerusalem which marked the beginning of the series of calamities ending with the destruction of the (First) Beit Hamikdash.
Interestingly, there are many customs and practices that we perform throughout the year זכר לחורבן, i.e. in order to remember and recall the destroyed Temple. These include leaving a small part of our home undecorated, and the breaking of a glass at a wedding. Given this, it seems that we should maintain a regular – if not perpetual – awareness of this void, and of the fact that this world is yet to be fully redeemed.
Additionally, the Rambam (Hilchot Ta’aniot 5:1) writes how every fast day should be a stimulus for us to stir our hearts and improve our ways, and just like the concept of היסח הדעת which teaches us that there are things that we must constantly focus our attention towards, our ability to make choices at any moment to live a better life should be something that is constantly on our mind.
Finally, the 10th of Tevet was established by the Chief Rabbinate of Israel as the Yom HaKaddish HaKlali – the day set aside for the recital of kaddish of all those who were murdered during the Shoah whose date of death is unknown. And especially as each new generation is born, and more survivors pass on, we must not forget our responsibility to bear witness both ‘for the dead, and the living’, and knowing what we know of the Holocaust and what our people experienced, we have a duty to remember the Holocaust and the memory of those – including those whose names are known as well as those whose names we may never know – who were so brutally murdered.
Ultimately, just as today’s daf speaks about the concept of היסח הדעת and the practices, concepts and objects towards which we are urged to focus our undivided attention, today’s fast is all about היסח הדעת – and how we must maintain a constant consciousness of the חורבן of the Temple, of our ability to make positive choices, and of our need to remember, mourn, and honour all those who were murdered during the Shoah.