Kalach Pitchei Chokhmah and Tanya

Both texts invoke the kav (קו) as the mechanism by which Ein Sof acts within the chalal after tzimtzum. Text 1 emphasizes the kav as the vehicle through which Ein Sof's infinite nature operates within finite creation while maintaining both transcendence and immanence (הקו הוא מה שהוא לפי שלמותו). Text 2 emphasizes the kav as a garment (מלובש) channeling tzimtzum to create vessels of limitation (בחינת גבול על־ידי צמצום אור האין־סוף). Text 1 focuses on the paradox of infinite power working through finite channels; Text 2 emphasizes the kav's role in enabling the tzimtzum itself and creating bounded vessels. The conceptual focus differs—one stresses Ein Sof's operational continuity, the other stresses how limitation is established through the kav.