Once saved Always saved?!!?

"Once Saved, Always Saved?"
"With regard to despair, every appetitive movement that is conformed to a false intellect, is evil in itself and sinful. Now presumption is an appetitive movement, since it denotes an inordinate hope. Moreover it is conformed to a false intellect, just as despair is: for just as it is false that God does not pardon the repentant, or that He does not turn sinners to repentance, so is it false that He grants forgiveness to those who persevere in their sins, and that He gives glory to those who cease from good works: and it is to this estimate that the movement of presumption is conformed." - St. Thomas Aquinas ("Summa Theologica" 13th century A.D.)
"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
"And if some of the branches be broken off, and thou, being a wild olive tree, wert graffed in among them, and with them partakest of the root and fatness of the olive tree; Boast not against the branches. But if thou boast, thou bearest not the root, but the root thee. Thou wilt say then, The branches were broken off, that I might be graffed in. Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear: For if God spared not the natural branches, take heed lest he also spare not thee. Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off. And they also, if they abide not still in unbelief, shall be graffed in: for God is able to graff them in again." - Romans 11:17-23
What the Catechism of the Catholic Church says on "Once Saved, Always Saved:"
161. "Believing in Jesus Christ and in the One who sent him for our salvation is necessary for obtaining that salvation. [Cf. Mk 16:16 ; Jn 3:36 ; Jn 6:40 ; et al.] 'Since 'without faith it is impossible to please (God)' and to attain to the fellowship of his sons, therefore without faith no one has ever attained justification, nor will anyone obtain eternal life 'But he who endures to the end.'']"