The past tense of swear on a stack of Bibles is swore on a stack of Bibles.
The third-person singular simple present indicative form of swear on a stack of Bibles is swears on a stack of Bibles.
The present participle of swear on a stack of Bibles is swearing on a stack of Bibles.
The past participle of swear on a stack of Bibles is swore on a stack of Bibles.