Many biblical doctrines are misunderstood because of the way Scripture can appear to support numerous opposing views within Soteriology (the doctrines of salvation). This is because nearly any false teaching can be supported on partial Scripture, but truth is supported on the whole. (Hermeneutics—Scripture interpreting Scripture). As you may know, in Soteriology there are essential and non-essential scriptural doctrines concerning the impartation of Grace (receiving salvation), i.e. believing that salvation is only through Christ is essential doctrine for receiving salvation; believing O.S.A.S. (once saved always saved—which I believe Scripture supports) is non-essential for receiving salvation. We are all aware there is a multitude of Christians who have numerous opposing beliefs within non-essential doctrine, but it is within essential doctrine that unification is established in the "Household of God" (Eph 2:19). Essential doctrine establishes faith and non-essential doctrine establishes growth in faith. Therefore, Christians who unknowingly believe in the false non-essential and also disbelieves in the true non-essential will be impeded in their spiritual growth, but will be in the faith with the essentials. Weakness in the faith refers to misunderstanding, being ignorant of, or disbelieving in a scriptural doctrine, in which case impedes one from using it for learning and encouragement. Paul's indication of one being "weak in the faith" in Romans 14 was in similar reference to what Peter encountered in his "Joppa" vision (Acts 10:14, 15), which indicates that Peter was ignorant at that time (the Lord was revealing this for the first time) that in the "New Covenant" dispensation, the ordinances which were against the eating of certain animals was "taken away" (Heb 10:9; 1 Tim 4:4, 5; Matt 15:11), which Peter eventually learned that He was also referring to the receiving of the Gentiles. This example of Peter's is analogous to any unlearned true scriptural doctrine and if the believer is unaware of it, the teaching cannot be received and utilized. All Christians will be "caught up together" at the same time, “to meet the Lord in the air” (1 Thess 4:17) and the only historical difference between them will have been the quantity of encouragement due to spiritual growth. Simply put, not finding truth results solely from not seeking it (Matt 7:7; Luke 11:9).