Firmino has just one year remaining on his contract at Anfield and has been linked with a move to Juventus.
The Brazil international joined Liverpool from Hoffenheim in the summer of 2015 and was part of a famous attacking trident that included Mohamed Salah and Sadio Mane for the last five years.
But Liverpool's famous front three were broken up early in the summer transfer window when Mane departed for Bayern Munich.
While Salah has signed a new contract, Firmino has also been linked with an exit but Klopp is keen to retain the 30-year-old's services.
FA Cup holders Liverpool play Premier League champions Manchester City in the Community Shield at the King Power Stadium on Saturday and ahead of the game Klopp reiterated a desire to hold onto his prized asset.
"Bobby is crucial for us," Klopp said during a press conference on Thursday. "Bobby is [the] heart and soul of this team.
"The way we played in the last few years was only possible because of Bobby. That's why I’m really happy he could train the majority of the time here in the pre-season so far and everything looks really good.
"I am absolutely fine and, for me, there's no doubt about his quality. All the rest, we will see how this year goes, but yes, he is essential for us."
Firmino has won the Premier League, Champions League, UEFA Super Cup, FIFA Club World Cup, FA Cup and Carabao Cup in his time at Liverpool.
