Lambert said: "As far as I'm concerned the guy's here and he isn't going anywhere until I say so - that's the bottom line."
Benteke has scored 11 goals for Villa in a challenging season that has seen the club drop to 17th in the Premier League - just a point above the relegation places.
He said: "He has been phenomenal - he's 22 years of age, he's got so much to learn and so much to give to the game.
"If he keeps progressing the way he's going he'll be a top player. What he's done for this football club in the short time he's been here - he's got to sustain that over not just a year but over his career."