First, we must recall that much (not all) of the NT is written and steeped in Hebrew idiom. This an example of Hebrew hyperbole. But let me get to that in a moment. First the meaning of the word, "disciple".
The Greek word μαθητής (mathetes) according to BDAG has two basic meanings:
- one who engages in learning through instruction from another, pupil, apprentice, eg, Matt 10:24, Luke 6:4, etc. I particularly like the "apprentice" translation as this Greek word comes directly from the ancient guild system where a local master tradesman would run a school and teach apprentices his skills. The primary function of the apprentice was to learn to imitate the master. Thus Jesus tells us to imitate Him and teach others to do the same, Matt 28:19, 20.
- one who is rather constantly associated with someone who has a pedagogical reputation or a particular set of views, disciple, adherent, eg, Matt 9:14, 11:2, 10:1, 11:1, 28:16, 8:21, etc. Acts uses μαθητής (mathetes) almost exclusively to denote the members of the Christian community of believers, Acts 6:1, 7, 9:19, 11:26, 29, 13:52, 15:10, etc.
Note especially that such "disciples" were often martyrs and under such circumstances they clearly valued their faith and trust in Jesus much more than other earthly associations as demonstrated by their willingness to die for their Lord. Indeed, Jesus warned his followers that family members will betray the disciples:
Matt 10:21, Brother will betray brother to death, and a father his
child; children will rise against their parents and have them put to
death. See also Mark 13:12.
It is in this sense that Jesus, in Luke 14:26, is telling the disciples that they must love Him supremely over all others, using classic Hebrew hyperbole.
Ellicott observes on Luke 14:26,
If any man come to me, and hate not his father.--Like words had been
spoken before, as in Matthew 10:37-39, where see Notes. Here they
appear in a yet stronger form, "not hating" taking the place of
"loving more," and they are spoken, not to the Twelve only, but to the
whole multitude of eager would-be followers. Self-renunciation,
pushed, if necessary, to the extremest issues, is with Jesus the one
indispensable condition of discipleship. He asks for nothing less than
the heart, and that cannot be given by halves.
The Pulpit commentary also says:
If any man come to me, and hate not his father, and mother, and wife,
and children, and brethren, and sisters, yea, and his own life also,
he cannot be my disciple. The Lord's teaching throughout, in parable
and in direct saying, pressed home to his followers that no home love,
no earthly affection, must ever come into competition with the love of
God. If home and his cause came ever into collision, home and all
belonging to it must gently be put aside, and everything must be
sacrificed to the cause.