"Nevertheless I am not ashamed: for I know whom I have believed, and am persuaded that he is able to keep that which I have committed unto him against that day." (2 Timothy 1:12)
The apostle Paul uses a precision of synonyms. We are to "know" the One in whom we have believed and to be "persuaded" that He is able to "keep" us.
The knowledge Paul cited (Greek i'do) emphasizes mental understanding as opposed to experiential knowledge or intuitive perception. I'do coupled with the word for persuasion (Greek peitho) strengthens the assurance Paul is promising. Our confidence is not based on mere emotion but a on clear grasp of God's secure salvation. Perhaps a quick survey of other passages will encourage your heart as you read this:
"Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life" (John 5:24).
"Being confident of this very thing, that he who hath begun a good work in you will perform it until the day of Jesus Christ" (Philippians 1:6).
"God. . . hath begotten us again to . . . an inheritance incorruptible and undefiled, and that does not fade away, reserved in heaven for you, Who are kept by the power of God through faith for salvation ready to be revealed in the last time" (1 Peter 1:3-5).
"Now unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy, To the only wise God our Saviour, be glory and majesty, dominion and power, both now and ever. Amen" (Jude 1:24-25).
What marvelous promises! Our surety is based on who God is, rather than on our own individual steadfastness. HMM III