It might seem that the controversies of the first-century Church could be dry reading to modern eyes. However, the way this particular controversy, told in today's first reading, was handled meant that the vast majority of nearly everyone who is reading this teaching now has the opportunity to be saved!
If the members of the early Church were not listening closely to the Holy Spirit, they could have closed their hearts to the leading of the Holy Spirit, relied on the historical precedent of their forefathers, and decided that only practicing Jews could be Christians (see Acts chapters 11 and 15).
This means that most of us would be excluded from God's Kingdom, unless we converted to Judaism. However, "God has granted life-giving repentance even to the Gentiles," that is, to non-Jews (Acts 11:18). Now we have access to Jesus and to eternal life (see Eph 3:12).
If you were aware that the decisions you make today would impact the salvation of people two thousand years from now, how would you act? Hopefully, you would be moved to listen attentively to the Holy Spirit today. "If today you hear His voice, harden not your hearts" (see Heb 3:15). Even if only one person would be led to salvation merely by observing you, that person might lead thousands to salvation in their life. Therefore, live for Jesus today so others will live for Him in the future.