"We won't be selling any of our best players. No one is for sale here," Redknapp told a news conference at the club's training ground on Friday.
"There is going to be no one leaving here in January that I want to keep, that's for sure. If we do anything we will add to the squad, we won't be weakening the squad at all. That's the message from both myself and the chairman [Daniel Levy].
"If one or two positions open up where fringe players want to go then we will look at that but we are not going to sell our best players or anyone we want to keep."
Tottenham fought off at least three bids from Chelsea for Croatia midfielder Modric in the last transfer window - with their London rivals having offered up to 40 million pounds according to media reports - despite the 26-year-old playmaker saying he wanted to leave White Hart Lane.
Modric has been a key factor in Tottenham's impressive form since they lost their opening two matches to Manchester United and Manchester City - a run which has seen them win 10 and draw one of their next 11 matches.
