The imperfect tense (ἐδίωκον) might be rendered began to persecute, as this is an opening of hostilities against Jesus, or, more probably, corresponds with the same tense in ἐποίει, he did, or better, was wont to do. Διώκω, to persecute, is originally to run after, to pursue with hostile purpose, and thence to harass.
And sought to kill Him
The best texts omit.
See above. Godet observes: “the imperfect malignantly expresses the idea that the violation of the Sabbath has become with Him a sort of maxim.”