By Grace alone!

For by grace are you saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest anyone should boast (Ep.2:8-9).

It is only by God's grace that men are saved. Jesus shed His blood to save men from their sin's, without the shedding of blood there is no remission of sins.

Jesus secures the believer's salvation!

Jesus said I came down from heaven, not to do my own will, but the will of Him that sent me.
And this is the Father's will which has sent me, that I should lose nothing, but should raise it up again at the last day.
And this is the will of Him that sent me, that everyone which seeth the Son, and believeth on Him, may have everlasting life: and I will raise him up at the last day (Jn.6:39-40).

No one can come unless the father draws him!

No man can come to me, except the Father which hath sent me draw him: and I will rasie him up at the last day.
And He said, therefore said I unto you, that no man can come unto me, except it were given unto him of my Father (Jn.6:44,65).

Only His sheep are eternally secure!

My sheep hear my voice and I know them, and they follow me: and I give unto them eternal life; and they shall never perish, neither shall any one pluck them out of my hand.
My Father, which gave them to me, is greater than all; and no man is able to pluck them out of my Father's hand (Jn. 10:27-29).

His sheep have been chosen before the foundation of the world and He has predestinated us according to His own good pleasure which He purpose in Himself!

According as He has chosen us in Him before the foundation of the world, that we should be holy and without blame before Him in love:
Having predestinated us unto the adoption of children by Jesus Christ to Himself, according to the good pleasure of His will,
To the praise of His grace, wherein He hath made us accepted in the beloved.
In whom we have redemption through His blood, the forgiveness of sins, according to the riches of His grace; Wherein He hath abounded towards us in all wisdom and prudence; having made know unto us the mystery of His will, according to His good pleasure which He has purposed in Himself: That the dispensation of the fullness of times He might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in Him:
In whom also we have obtained an inheritance, being predestinated according to the purpose of Him who worketh all things after the counsel of His own will: That we should be to the praise of His glory, who first trusted in Christ. In whom you also trusted, after that you heard the word of truth, the gospel of your salvation in whom also, after that you believed, you were sealed with that Holy Spirit of promise (Ep.1:4-13).