Talking to reporters at her residence in Patna, Ms Rabri expressed concern over the health of her husband, who is in his 70s and has undergone a heart surgery.
"We have to honour the court's judgement. Our workers across Bihar and in other parts of the country should stay calm and not get disheartened," she said.
"They should remember 'bhagwan ke ghar der hai andher nahin' (there is delay in divine dispensation, but not injustice)," she said.
"Yesterday we were confident that he (Lalu) would be set free. Some news channels also flashed news to that effect, only to retract a few seconds later. Now we have to put up with whatever has happened.
"I just hope that he stays healthy and takes his medicines on time. He is a heart patient who has undergone a major surgery and we have apprised the court of his medical condition," Ms Rabri said.
Meanwhile, Yadav's elder son and party MLA Tej Pratap Yadav tried to put up a brave front saying, "Lalu is not the name of a person, but that of an ideology. We have no worries. He will get justice and come out of jail soon."
Yadav, whose quantum of sentence is expected to be announced on January 3, has been sent to a jail in Ranchi.
Top RJD leaders, including Yadav's younger son Tejashwi Yadav and party national vice-president Raghuvansh Prasad Singh, are camping in Ranchi.