“You know when I sit and when I rise; You perceive my
thoughts from afar. You discern my going out and my
lying down; You are familiar with all my ways. Before a
word is on my tongue—You know it completely, O Lord!”
Psalm 139:2-4

“For I know the things that come into your mind,
every one of them”
Ezekiel 11:5

Sacred doctrine makes use of these authorities [philosophers and human arguments] as extrinsic and probable arguments; but properly uses the authority of the canonical Scripture as an incontrovertible proof, and the authority of the doctors of the Church [the theologians] as one that may be properly used, yet merely as probable. For our faith rests upon the revelation made to the apostles and prophets, who wrote the canonical books, and not on any revelations (if there were any) made to other doctors.-St. Thomas, the Summa (1. Q1. 8)

From an infallible source:

It firmly believes, professes, and proclaims that those not living within the Catholic Church, not only pagans, but also Jews and heretics and schismatics cannot become participants in eternal life, but will depart "into everlasting fire which was prepared for the devil and his angels" [Matt. 25:41], unless before the end of life the same have been added to the flock; and that the unity of the ecclesiastical body is so strong that only to those remaining in it are the sacraments of the Church of benefit for salvation, and do fastings, almsgiving, and other functions of piety and exercises of Christian service produce eternal reward, and 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. (Denzinger 714).