Within commentaries such as Ta’anit 2a and the Sifre (Piska 41) on Devarim (see also Devarim 11:13) ’to serve with all your heart’ is being defined as Tefillah - prayer, which is the reason why Tefillah is being called Avodah Shebalev. I have 2 questions I would like to get an answer to: 1. Why is it exactly that the service of the heart is being identified as Tefillah, isn’t all that we do out of our heart service? 2. The verse of Devarim follows with ’all your Nefesh’ and with ’all your me’od’, so what is the service of the Nefesh? And what is the service with all your me’od? I want to thank you in advance for your time and effort.
1. The original “Avodah” (service) was the sacrifices in the Beit HaMikdash, but since its destruction almost 2,000 years ago, what remains is just “Avodah Shebalev” (service in the heart). The word in Hebrew for sacrifices is “Korbanot” from the root “Karov”= to come closer, and although all of the mitzvot bring us closer to God and His ideals, the most direct (!) act of coming closer is through speaking to Him, prayer. Most other mitzvot are directives to be (!) like Him, while prayer is to speak with He Himself, like sacrifices which combined prayer and “giving” to Him, which also developed our two-way personal relationship with Him. 2. The Talmud (Brachot 54a) teaches that to serve God with “all of your Nefesh (soul)” means even if the Torah may (rarely) obligate us to give our lives for our Judaism, and the service with “all your me’od” (=with all of your “very”) is a beautiful term, teaching to totally serve Him with every one of the faculties and tools at our disposal.