Spurs manager believes if the club show their desire to challenge for silverware, star playmaker Luka Modric will stay at White Hart Lane and not be tempted to move to Chelsea
The 25-year old has been subject to a number of bids from Chelsea and intense speculation about his future, and Redknapp believes that to keep Modric Tottenham must strengthen their squad and look to challenge for silverware.
Redknapp told BBC Radio 5Live’s 'Sportsweek' programme: "I think we have to show him our ambition, which we will do.
"If we can add one or two good players to our squad there's no reason we can't have another great season.
"So Tottenham could be a great club for him to stay with for the next few years. That's what we're hoping for."
Modric expressed his desire to leave White Hart Lane after Spurs rejected a £22 million bid for him from Chelsea, but Redknapp believes that for Tottenham to go forward, they cannot afford to sell the Croatia international.
Redknapp added: "Chelsea are not the only club that have been in for him.
"There have been other clubs - top, top clubs.
"But if Tottenham are looking to go anywhere we can't be selling Luka. We have to do something to keep him at the club. We can't afford to sell Luka Modric if we want to be a successful club.
"He's a fantastic lad. You'll never meet a better lad than Luka.
“I suppose he's seen a massive contract and the chance to win the Premier League and play in the Champions League and that's what he wanted.
"But we want that as well. We want to get back in the Champions League and we need him to help us do that.
"If [spurs chairman] Daniel [Levy] is saying no he really can't be seen to be going back on that now. He's made a very strong statement. I wouldn't see Daniel backtracking on that at any price."
Modric has reportedly been subject to attention from both Manchester City and Manchester United, but is believed to prefer Chelsea, should he change clubs, as he would like to stay in London.