It must be the phase in my Jewish prayer evolution for me to begin to understand the famous phrase, "service of the heart." Historically, Jews offered sacrifices in the Holy Temple in Jerusalem, but since the destruction of the Holy Temple we no longer offer animal, grain and oil sacrifices. That part is factual and simple.
What isn't so simple is when and how Jewish communal prayers recited in synagogues developed as a replacement for Temple sacrifices. Biblical scholars and archeologists have had discussions and disagreements on this topic for centuries.
The transition from bringing sacrifices to a priest to speaking personal and communal prayers was an enormous cultural change. It didn't happen all at one time or in one place.
What matters most to me is that my prayers are a genuine service of my heart, offered humbly and respectfully before my Almighty God.