Benteke penned new terms last week, just a fortnight after handing in a transfer request.
"He's only 22 years of age, he'll make mistakes, like everybody else," said Lambert.
"Everybody makes mistakes throughout their life. You're asking somebody of 22 years of age who has a massive responsibility on his shoulders.
"I knew what was going on from day one, it's never nice.
"But he's a really good guy, a really nice kid and the most important thing is getting him back in the side and that will happen during the next few weeks."