The Apostle Paul criticized Peter for expecting Gentile believers to adhere to Jewish customs, while he himself, being a Jew, did not fully observe the law. Paul emphasized that justification cannot come through the deeds of the law; rather, salvation is through faith in Jesus Christ and following His commandments. He stated that if one believes the law can lead to justification, then, in that case, Christ's sacrifice was rendered meaningless (see Galatians 2:16-21). Chrysostom elaborated on this by noting that adhering to the law undermines the gospel, and if the entire law is to be observed, it compromises the doctrine of justification by faith. He questioned the logic of selective observance—if one is to follow any part of the law, they should follow it all, or risk being a transgressor, implicating Christ as the catalyst for such a transgression because He allows for the relaxation of the law's demands.
Returning to Jesus' parable, we see how the Pharisees frequently admonished His disciples for not following their stringent legal requirements, such as harvesting grain on the Sabbath, neglecting fasts, and dining with unwashed hands. Each time, Jesus defended them. In this instance, when the Pharisees alongside John’s disciples confronted His followers for missing fasts, the Lord not only justified them but also articulated His teaching's incompatibility with rigid adherence to Jewish law.
In this parable, which may be subject to different interpretations, it can be understood—following the interpretations of Paul and Chrysostom—as a challenge to the Pharisees. Jesus argued that they sought to confine His disciples within the old garments of their rituals and traditions, while He called for them to embrace the new attire of grace and love. He pointed out that one cannot don a new garment without discarding the old and that attempting to patch the worn garment with new fabric will only lead to greater damage. Likewise, young wine cannot be placed into old wineskins, for they cannot accommodate it. Thus, He encouraged His disciples to embrace His teachings fully, shedding the old ways.
Though they may not yet embody the full spirit of Jesus' revolutionary message, they have begun to appreciate its superiority over traditional teachings. In a similar way to how one who enjoys fine wine would not return to inferior offerings, His disciples, having tasted the goodness of His message, would not revert to the teachings of the Pharisees. The parable’s assertion that no one who has tasted fine wine desires inferior wine (Luke 5:39) may initially seem contradictory when discussing old garments and wine; however, understanding that valuable wine is contrasted with the inferior clarifies this. Thus, the message of the parable becomes evident: those who have been enriched by Christ's teachings will not seek to return to old ways.