The Bible was given by inspiration of God to be the rule of faith and life. The whole counsel of God concerning all things necessary for his own glory and man's salvation, faith, and life, is either expressly stated in the Bible or by good and necessary inference may be deduced from it. It is the only infallible rule of faith and practice.
Link here to
The Westminster Standards
The Westminster Confession of Faith together with its catechisms make up our Secondary Standards. These, being written by men, are fallible and must always remain subordinate to God's Holy Word. Yet we believe these contain an accurate system of doctrine taught in the Holy Scriptures, so our ministers, ruling elders and deacons all vow that they receive and adopt these.
Link here to Westminster Standards
Book of Church of Order
The Book of Church of Order contains the government, discipline, and worship of the OPC and serves as our tertiary standards.
Link here to Book of Church Order