Was Jesus' job just to train a group of twelve disciples so he could have twelve apostles? Teaching happens by instruction and example. At the start "He sat down and began teaching the people" (Lk 5:5). He directed some of them to "'go and learn what this means'" (Mt 9:13). "All the people were coming to Him, and He was teaching them" (Mk 2:13). "He was stating the matter plainly" (8:32) and "summoned the crowd with His disciples" (:34). He was "sent only to the lost sheep of the house of Israel" (Mt 15:24) but they asked, "'Why is your Teacher eating with the tax collectors and sinners?'" (Mt 9:11). "On the sabbath He entered the synagogue and began to teach" (Mk 1:21). They asked if it was "'a new teaching with authority!'" (:27). The concordance defines it as "with competency and strength with right and jurisdiction." One time James and John asked, "'Teacher, we want you to do for us whatever we ask of You'" (Mk 10:35) Jesus responded, "'Are you able?'" (:38).
Jesus was building upon what was presented in the Old Testament. One thing which was required back then was "'to fear the Lord your God, to walk in all His ways'" (Dt 10:12). It was to fulfill that covenant. To walk in this way is to follow God. Their problem was that "they forsook the Lord . . . and followed other gods" (Ju 2:12). They were a "rebellious people, who walk in the way which is not good, following their own thoughts" (Isa 65:2). Peter also cited that "many will follow their sensuality, and because of them the way of truth will be maligned" (2Pe 2:2). Elijah asked, "'If the Lord is God, follow Him; but if Baal, follow him'" (1Ki 18:21). However if you "walk by the Spirit, you will not carry out the desire of the flesh" (Gal 5:16). His "sheep follow him because they know His voice'" (Jn 10:4). "'A stranger they simply will not follow'" (:5). "'My sheep hear My voice, and I know them, and they follow Me'" (10:27). "'Whoever does not . . . come after Me cannot be My disciple'" (Lk 14:33).