Just what do you mean "the oracles of God?" And is the sacred calendar a part of them? There are only four places in the New Testament that speak of the oracles of God:
Acts 7:38 reveals that Moses received "the lively oracles to give unto us."
Rom. 3:2 states, without apology, that "the oracles of God" were COMMITTED TO THE JEWS.
Heb. 5:12 speaks of "the first principles of the oracles of God" and 1 Pet. 4:11 states that those whom God has gifted to speak should "speak as the oracles of God."
All of these examples use the Greek word logion (Strong's Concordance #3051) that means an utterance-oracle. That word comes from logios (#3052) that means an orator-eloquent. And that word comes from logos (#3056), which means something said (including the thought); a topic; the word. The words, thoughts and topics of God given to the Jews (to PRESERVE for all mankind) includes "the covenants, the law, the service of God, the promises," among many other things (Rom. 9:4).
How can we properly serve God without knowing His plan of salvation as revealed through His holy days? And how can we know the CORRECT DATES to observe the holy days without a SACRED CALENDAR? Besides, what other purpose is there for a calendar? (Gen. 1:14; Ex. 12:2).
WHO has preserved this knowledge? The Asians? Maybe the Greeks? How about the Africans? No! Only the JEWS have kept God's sacred calendar and made us aware of it and God's holy days! Without the Jews faithfully fulfilling their commission to preserve this knowledge we would've been left in the dark! (Hos. 11:12). But GOD IS FAITHFUL who has left us a witness in every generation.
But what if some Jews weren't faithful? What if different Jewish groups were divided on these holy issues? Let God's Word answer: "For what if some did not believe? shall their unbelief make the faith of God without effect? God forbid: yes, LET GOD BE TRUE, but every man a liar..."(Rom. 3:3). God is quite capable of seeing that His light will shine through doctrinal darkness. After all, GOD'S WORD IS AT STAKE! Let's not limit the Holy One of Israel!
God's empowered the Jews - despite themselves - to preserve His Word. They are the only people on earth that God has blessed and ordained to fulfill such a calling! God will not retract His Word or renege on this gift and responsibility that He's graciously bestowed upon Judah! (Gen. 49:10, Rom. 11:29; Num. 23:19).
In Jesus' day there were different Jewish groups at odds with each other (like Christianity today), and Christ often publicly corrected them where they were wrong. He's done the same to His Church throughout the ages, pointing out our strengths and weaknesses (Rev. 2; 3). But Jesus clearly revealed WHICH Jewish group had GOD'S SEAL OF APPROVAL! Only the PHARISEES - of all the various splinter groups - had received the GOD-GIVEN AUTHORITY to keep/preserve/retain and teach "the oracles of God."
The apostle Paul also stood with the Pharisees against the other sects (Acts 23:6). Will we accept God's Word on this subject or resist change? Are we any better than our forefathers who clung to their vain traditions? (Acts 7:51; Mark 7:7). We condemn ourselves and our religion when we refuse to be corrected and prefer to remain comfortable in our pews! How proud (Sodom) and stubborn (Egypt)! (John 3:20; Amos 6:1; Rev. 11:8).
Jesus didn't stutter when He taught that "the scribes and PHARISEES sit in Moses' seat" (Matt. 23:2). Even so, Jesus went on to rebuke certain attitudes and practices that weren't consistent with the Scriptures, but He didn't throw the baby out with the bathwater since He testified that "salvation is of the Jews!" (John 3:22).
God made sure that the PHARISEES' biblical traditions would survive and prevail. However, the faulty teachings of the Sadducees and Samaritans (whose blind dates for Passover and Pentecost many in God's Church shamefully follow) are history!
Today the Jewish nation of Israel follows the correct holy dates as established by the Pharisees. They don't have any question or controversy over it. On this holy topic they all "speak the same thing." And, thankfully, bold members of God's Church are beginning to see the light on this subject and are accepting God's correction and opportunity to change.
May we embrace the "oracles of God" and overcome the obstacles of men! (Luke 11:52).