Please make your case that we need to make our case using the Bible.
Because we know that it’s inspired by the Holy Spirit, is infallible, and has not contradictions or errors. Now, you may need to tell us which of the following positions of the RCC are the infallible ones and inspired by the Holy Spirit.
Pope Boniface VIII, Unam Sanctam: “We declare, say, define, and pronounce that it is absolutely necessary for the salvation of every human creature to be subject to the Roman Pontiff.” — Pope Boniface VIII, Unam Sanctam (Promulgated November 18, 1302) http://www.fordham.edu/halsall/source/b8-unam.html
St. Thomas Aquinas: It is also shown that to be subject to the Roman Pontiff is necessary for salvation. St. Thomas Aquinas, Against the Errors of the Greeks, Pt. 2, ch. 36 http://dhspriory.org/thomas/ContraErrGraecorum.htm#b38
…that no one, whatever almsgiving he has practiced, even if he has shed blood for the name of Christ, can be saved, unless he has remained in the bosom and unity of the Catholic Church.” Pope Eugene IV, Cantate Domino, Bull promulgated on February 4, 1441 (Florentine style), proclaimed “ex cathedra” (infallible).
The Holy Catholic Church teaches that God cannot be adored except within her fold; she affirms that all those who are separated from her will not be saved. (Pope St. Gregory the Great, “Moralia,” XIV:5)
Neither the true Faith nor eternal salvation is to be found outside the Holy Catholic Church. It is a SIN to believe that there is salvation outside the Catholic Church. (Ven. Pope Pius IX, Singulari Quidem, March 17, 1856; cf. also OUR GLORIOUS POPES, Slaves of the Immaculate Heart of Mary, Cambridge, MA: 1955, p.168)
Then a change,
RCC: 846 How are we to understand this affirmation, often repeated by the Church Fathers?[335] Re-formulated positively, it means that all salvation comes from Christ the Head through the Church which is his Body:…Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.[336]
..there are many who honor Sacred Scripture, taking it as a norm of belief and a pattern of life, and who show a sincere zeal. They lovingly believe in God the Father Almighty and in Christ, the Son of God and Saviour. (Cf. Jn. 16:13) They are consecrated by baptism, in which they are united with Christ. They also recognize and accept other sacraments within their own Churches or ecclesiastical [Protestant] communities…
They also share with us in prayer and other spiritual benefits. Likewise we can say that in some real way they are joined with us in the Holy Spirit, for to them too He gives His gifts and graces whereby He is operative among them with His sanctifying power. Some indeed He has strengthened to the extent of the shedding of their blood. — LUMEN GENTIUM: 16.
…those who are baptized in these communities are, by Baptism, incorporated in Christ and thus are in a certain communion, albeit imperfect, with the Church.” “All who have been justified by Faith in Baptism are incorporated into Christ: they therefore have a right to be called Christians, and with good reason are accepted as brothers by the children of the Catholic Church.” — http://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_20000806_dominus-iesus_en.html
RCC: 847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church: Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience – those too may achieve eternal salvation.[337]
We can rely on the consistency of scripture. How about your RCC?