וְאֶ֨לֶף אִ֣ישׁ עִמּוֹ֮ מִבִּנְיָמִן֒ וְצִיבָ֗א נַ֚עַר בֵּ֣ית שָׁא֔וּל וַחֲמֵ֨שֶׁת עָשָׂ֥ר בָּנָ֛יו וְעֶשְׂרִ֥ים עֲבָדָ֖יו אִתּ֑וֹ וְצָלְח֥וּ הַיַּרְדֵּ֖ן לִפְנֵ֥י הַמֶּֽלֶךְ׃
Avec lui étaient venus mille hommes de Benjamin, plus Ciba, serviteur de la maison de Saül, avec ses quinze enfants et ses vingt esclaves; et ils traversèrent le Jourdain en présence du roi.
Siftei Chakhamim
Onkelos translates it וצלח [he split] as in וצלחו [they split]... It seems that Rashi is not proving from Onkelos [that ויבקע means “splitting”]. Rather, he is explaining that [also Onkelos’s translation of] צלח is “splitting,” as in (Shmuel II 19:18): “They split (וצלחו) the Jordan.”
Rashi
ויבקע AND HE CLEAVED [THE WOOD] — Its rendering in the Targum וצלח has the same meaning as the verb in (2 Samuel 19:18) And they rushed into the Jordan”, which signifies cleaving the waters; old French fendre; English to split.