Psalms 18:27 Commentary: Rashi

עִם־נָבָ֥ר תִּתְבָּרָ֑ר וְעִם־עִ֝קֵּ֗שׁ תִּתְפַּתָּֽל׃

With the pure Thou dost show Thyself pure; and with the crooked Thou dost show Thyself subtle.