यद्बलः सामन्तस्तद्विशिष्टबलमाश्रयेत् ॥ कZ_०७.२.०६ ॥
yadbalaḥ sāmantas tadviśiṣṭabalam āśrayet
If the neighboring (feudatory) ruler has such-and-such strength, one should seek shelter with a power that is distinctly superior to that strength.
Not just ‘strong’, but clearly stronger than the immediate threat—so protection is credible and deterrence works.