The Greek verb ethizō (ἐθίζω) means 'to accustom' or 'to train by habit/custom.' It is the verbal form of ethos (custom, habit) and appears once in Luke 2:27 describing the 'custom of the Law' regarding the presentation of a firstborn son at the Temple.
Luke 2:27 records that when Jesus was brought to the Temple as an infant, Simeon met them 'as the parents brought in the child Jesus to do for him what the custom of the Law required [ethizō].' The passage reveals something profound: the infant Jesus — the one who gave the Law — was subjected to the Law's requirements. This fulfills Paul's statement in Galatians 4:4: 'God sent his Son, born of a woman, born under the law, to redeem those under the law.' The Son of God entered the pattern of Torah observance not because He needed redemption but so that He might fulfill every requirement on behalf of those who do. Every act of Jesus' infancy and childhood was an act of covenantal obedience for us.