וַיִּשָּׁבַע֙ הַמֶּ֣לֶךְ שְׁלֹמֹ֔ה בַּֽיהוָ֖ה לֵאמֹ֑ר כֹּ֣ה יַֽעֲשֶׂה־לִּ֤י אֱלֹהִים֙ וְכֹ֣ה יוֹסִ֔יף כִּ֣י בְנַפְשׁ֔וֹ דִּבֶּר֙ אֲדֹ֣נִיָּ֔הוּ אֶת־הַדָּבָ֖ר הַזֶּֽה׃
Then king Solomon swore by the LORD, saying: ‘God do so to me, and more also, if Adonijah have not spoken this word against his own life.
Read halakhic rulings (Jewish law) on I Kings 2:23: and classical halakhic sources.