The Gemara says that where Baalei Teshuva stand, even complete Tzadikim can't stand. The Rambam explains that since Baalei Teshuva are used to sinning, it is harder for them to stop.
This raises a significant difficulty: If this is the explanation then the Gemara should have said that where people who used to sin and stopped stand, even complete Tzadikim can't stand. This is true even if the former sinner DIDN'T do Teshuva on the past!! Why does the Gemara emphasize that he did Teshuva???!!
[מרן ראש היהשיבה זצ"ל]
