Mark 6:34

They were as sheep not having a shepherd

(ησαν ως προβατα μη εχοντα ποιμενα). Matthew has these words in another context (Matthew 9:26), but Mark alone has them here. Μη is the usual negative for the participle in the Koine. These excited and exciting people (Bruce) greatly needed teaching. Matthew 14:14 mentions healing as does Luke 9:11 (both preaching and healing). But a vigorous crowd of runners would not have many sick. The people had plenty of official leaders but these rabbis were for spiritual matters blind leaders of the blind. Jesus had come over for rest, but his heart was touched by the pathos of this situation. So "he began to teach them many things" (ηρξατο διδασκειν αυτους πολλα). Two accusatives with the verb of teaching and the present tense of the infinitive. He kept it up.