The Ruzhiner Rebbe zy’a (Irin Kadishin Likutim) states that in our times – during the era of the last generation in exile – our main avodah is to strengthen our emunah. He compares the neshamos of Klal Yisroel to a body and says that just like a body has a head, torso and legs, so too Klal Yisroel is made up of such ‘body parts’. The early generations were ‘the head’, the middle generation were ‘the body’, and the final generations – the generations known as the ‘Ikvesah D’Meshicha’ (literally ‘the heels of Moshiach’) are ‘the feet’.
The head contains the five senses and the mind, while the body contains the understanding of the heart. Something one sees with his eyes does not require emunah, as it is clear to see and to believe in with one’s heart. The legs, however, contain no such senses. For the legs to ‘believe’ they need emunah. Therefore, the generations that are compared to the feet need to strengthen their emunah in order to believe that Hashem is fully in control of everything that occurs.
He says that it is very difficult for people in these lowly, downtrodden generations to excel in Torah, tefillah or avodas Hashem, but we can work on strengthening our emunah and, by doing so, even a little bit, we create a strong impression in Shomayim. Just like the feet need the head, the head also needs the feet to hold it up. Without the legs, the body and head would be unable to stand upright. So too, all previous generations depend on the final generations to hold everything up, and every little thing the final generations do to increase their emunah is greatly beloved by Hashem.