一以贯之

yī yǐ guàn zhī

(idiom) (of a principle, purpose etc) consistently upheld; adhered to from beginning to end

一

yī

one

以

yǐ

abbr. for Israel 以色列[Yi3 se4 lie4]

贯

guàn

to pierce through

之

zhī

(possessive particle, literary equivalent of 的[de5])