The BJP said it will take disciplinary action against Mr Sahni for his "reckless utterances".
"We will give a reward of Rs 1 crore to anybody who slaps Tej Pratap Yadav. The RJD leader had threatened to thrash our respected deputy CM inside his house (during the wedding of his son on December 3). We wish to pay Yadav in the same coin," Mr Sahni had said.
"We will also organise demonstrations in front of Yadav's house to put pressure on him to apologise to Sushil Modi," he had said.
The BJP leader was reacting to a recent video footage in which Mr Yadav, the elder son of RJD chief Lalu Yadav and a former state minister, was purportedly shown threatening to disrupt Sushil Modi's son's wedding and using the words "ghar mein ghus kar maarenge (will beat him inside his house)".
Mr Yadav's comments drew strong reaction from Sushil Modi, who asked Lalu Yadav to stop his son from making provocative speeches.
However, in response to Mr Sahni's remarks, a strongly-worded statement was issued by BJP state unit spokesman Suresh Rungta, who said, "Sahni has spoken in his personal capacity. The party condemns his statement and has nothing to do with it".
"The BJP has always been a votary of decorum and decency in public discourse... Sahni will therefore certainly face disciplinary action by the party," Mr Rungta added.