The Scot is out of contract at the end of the season and has insisted he does not expect to open talks over a new deal until the summer.
This has led to intense speculation that Moyes could be set to bring his Goodison Park reign to an end after more than a decade in charge.
"We haven't done too bad in the ten years or so that he has been here. It's not like we have under-achieved. If anything, we have slightly over-achieved in terms of budgets and transfer funds," said Jagielka.
"We don't have to feel that we have to prove anything. The manager has pretty much brought every single player in, bar one or two, so we are his players.
"He has made decisions that he wants to make. He has come out in the press and said he will not sign anything until the end of the season, which is fine with us."
Jagielka was talking after Everton's 2-2 draw with Oldham, which saw them into the FA quarter-final draw where they could face Wigan at home.
"Obviously, it will be nice to give him a quick reminder of how good we are by keeping this cup run going and pushing as high as we can up the Premier League," he said.
"At the end of the day, if we do win the cup and he doesn't sign, it will still be a fantastic feat for the players.
"We are a very close squad and we get on very well. As much as we go out there to do it for the manager, we do it for each other as well.
"Obviously, the fans, too. We had a good following today and the fans are brilliant, too. So there is more than one person there to play for."
@kalavrim @jelasfirsttouch, my point is not about profit on strikers (well it was to a certain extent), that was merely a microcosm of how moyes has not only improved the quality of the squad but also that he has done it by raising his own finances. Moyes is now a victim of his own success amongst everton fans and it troubles me. If David Moyes leaves everton I seriously fear for us, not immediatley but within 3-5 years I believe due to the finances, we will really struggle unless we somehow finance a new ground or recieve a rich owner, the latter I am not in favour of. We recieve roughly 800k per game match day income compared to liverpool and spurs, who are more than double that, with arsenal and united multiplying that figure by 4, we have no corporate seats which costs us majorly . First half of this season is the best football I have seen at goodison in my lifetime (season ticket since 95 minus the odd few years, i was born in 87, I am the jinx to why we have never won a title i think!) and to think he has done this spening 800k a year, 8.8m pound david moyes has left this club out of pocket in terms of transfers. Seriously, i may get some backlash for saying this, but far too many everton fans live in the 1980's with far too high expectations. we are no longer the school of science nor are we the "mersey millioaniares of the 60's, nor do we have the the ability to purchase the best players from the lesser teams in the league like the 1980's. Moyes is the only reason we are not in the bottom 6 year in year out, the only reason. D- marlostanfield