Well, I always ask, why are Peter, Paul and the others coming back with "reminders" so that they remain firm in the faith, if OSAS is true? Basically they are wasting their time writing for nothing!
"But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway." - 1 Corinthians 9:27
"If by any means I might attain unto the resurrection of the dead. Not as though I had already attained, either were already perfect: but I follow after, if that I may apprehend that for which also I am apprehended of Christ Jesus. Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind, and reaching forth unto those things which are before, I press toward the mark for the prize of the high calling of God in Christ Jesus." - Philippians 3:11-14
"And ye shall be hated of all men for my name's sake: but he that endureth to the end shall be saved." - Matthew 10:22
"But he that shall endure unto the end, the same shall be saved." - Matthew 24:13
"And ye shall be hated of all men for my name's sake: but he that shall endure unto the end, the same shall be saved." - Mark 13:13
"Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven." - Matthew 7:21
"Then said Jesus to those Jews which believed on him, If ye continue in my word, then are ye my disciples indeed." - John 8:31
"Blessed is the man that endureth temptation: for when he is tried, he shall receive the crown of life, which the Lord hath promised to them that love him." - James 1:12
"For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning. For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them." - 2 Peter 2:20-21