The mother of five has been detained since 2009 and faces the death penalty on alleged blasphemy charges if her final appeal is rejected.
Andrew Boyd, from Christian charity Release International, told Premier: "Many people who've been accused of blasphemy have their lives taken by vigilantes anyway, irrespective of what the courts decide.
"If the courts decide to revoke the death penalty there's likely to be an uproar in Pakistan.
"There are militants who want to see her hanged.
"If they go ahead and permit her to be hanged and executed for blasphemy, that's likely to lead to more trouble for Christians."
The Centre for Research and Security Studies in Islamabad says that since 1990 "52 people have been extra-judicially murdered for being implicated in blasphemy charges."
Asia Bibi was accused of blasphemy after bringing water for Muslim labourers she was working with in a field.
They refused to drink it, saying that she had made the water unclean because of her faith. Some form of argument followed.
Her family are in hiding.
Andrew Boyd told Premier that by finding her not guilty the judges presiding the case would be risking their own lives: "To overturn that death penalty will put each of them at risk.
"So we pray for the courage to revoke the death penalty.
"We pray for the President of Pakistan, that he will give Asia a pardon, that she will be set free and that he will make sure her family are protected."
Asia Bibi is thought to be Pakistan's highest profile prisoner and the world will be watching to see how the country decides her fate on Thursday.
If she is not acquitted she could be hanged within 30 days of the verdict.
Listen to Premier's Hannah Tooley speak to Andrew Boyd here: