A believer's thought life is probably one of the most powerful advocates of or enemies to his or her walk (2 Corinthians 10:4-5) - either leading into the light (Psalm 89:15; Ephesians 5:8; 1 John 1:7) or into darkness (Isaiah 59:8-10; Matthew 6:23; John 12:35).
The above scripture, I believe, gives a powerful prescription as to how to protects one's mind from the invasion of the oh-so-many things that are out there (and "in there") which seek to take over the thought life...that attempt to snatch us from the place of Glory at the right hand of the Father, where we are "alive together in Christ" (Ephesians 2:4-6) and slam us (hopefully only temporarily) into a dark and dismal "doubting castle" where temptation towards any type of sin and old nature response (Galatians 5:19-21) is great:
"Now there was, not far from the place where they lay, a castle, called Doubting-Castle, the owner whereof was Giant Despair, and it was in his grounds they now were sleeping...with a grim and surly voice, he (Giant Despair) bid them awake...They told him they were Pilgrims, and that they had lost their Way. Then said the Giant...you must go along with me. So they were forced to go, because he was stronger than they. They also had but little to say, for they knew themselves in a Fault. The Giant...put them into his castle, in a very dark Dungeon, nasty and stinking to the spirit of these two men..." (John Bunyan, from The Pilgrim's Progress, pp. 128-129)
How easy it is to lose our way when we start allowing entrance and entertainment to (or when they just break right on in...) thoughts that set themselves up against God's thoughts and Ways. So here again is that prescription, each part an extremely potent safeguard for our minds (Greek/Word Origins from Study Light):
"Finally, brethren, whatever things are true...
Greek: Alethes. Loving/speaking the truth.
Word Origin: A - The first letter. Christ is the Alpha: beginning and end.
Lanthano - To be hidden, secretly, unawares.
"Jesus said to him, 'I am the way, the truth, and the life. No one comes to the Father except through Me.'" (John 14:6)
"...the mystery which has been hidden from ages and from generations, but now has been revealed to His saints...which is Christ in you, the hope of glory." (Colossians 1:26-27)
...whatever things are noble,
Greek: Semnos. Also "honest" "honorable."
Word Origin: Sebomai - to revere, to worship.
“Rejoice greatly, O daughter of Zion! Shout, O daughter of Jerusalem! Behold, your King is coming to you; He is just and having salvation, Lowly and riding on a donkey, A colt, the foal of a donkey." (Zechariah 9:9)
whatever things are just,
Greek: Dikaios. Righteous, observing divine laws. Conformed to the will of God.
"There is a way that seems right to a man, But its end is the way of death." (Proverbs 14:12, 16:25)
"And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God." (Romans 12:2)
"For Christ also suffered once for sins, the just for the unjust, that He might bring us to God..." (1 Peter 3:18)
whatever things are pure,
Greek: Hagnos. Exciting reverence, sacred. Pure from carnality.
"Create in me a clean heart, O God, And renew a steadfast spirit within me." (Psalm 51:10)
"For He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him." (2 Corinthians 5:21)
whatever things are lovely,
Greek: Prosphiles. Acceptable, pleasing.
Word Origin: Pros - at, near, by, together.
Phileo - to love, friendship love.
Philos - one of the bridegroom's friends.
"No longer do I call you servants, for a servant does not know what his master is doing; but I have called you friends, for all things that I heard from My Father I have made known to you." (John 15:15)
whatever things are of good report,
Greek: Euphemos. Sound well, good repute.
Word Origin: Eu - good, well, well done.
Pheme - fame, report.
"His lord said to him, ‘Well done, good and faithful servant; you were faithful over a few things, I will make you ruler over many things. Enter into the joy of your lord.’" (Matthew 25:21)
"This is My beloved Son, in whom I am well pleased. Hear Him!”(Matthew 17:5)
if there is any virtue
Greek: Arete. Moral goodness, modesty, purity.
Word Origin: Arrhen - a male.
Airo - to raise, elevate, lift up, to raise from the ground. To bear or carry what has been raised.
"Therefore if there is any consolation in Christ, if any comfort of love, if any fellowship of the Spirit, if any affection and mercy, fulfill my joy by being like-minded, having the same love, being of one accord, of one mind...Let this mind be in you which was also in Christ Jesus, who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men. And being found in appearance as a man, He humbled Himself and became obedient to the point of death, even the death of the cross." (Philippians 2:1-2, 5-8)
and if there is anything praiseworthy—
Greek: Epainos. Approbation, commendation, praise.
Word Origin: Epi - of position, on, at, by, over, against
Aineo - to sing praises to honor God. To allow. To promise, vow.
"Sing praise to the Lord, you saints of His, And give thanks at the remembrance of His holy name." (Psalm 30:4)
"Whatever city you enter, and they receive you, eat such things as are set before you. And heal the sick there, and say to them, ‘The kingdom of God has come near to you.’" (Luke 10:8-9)
...meditate on these things.
In His Everlasting Love: the One Who Is the manifestation of those things that are true, noble, just, pure, lovely, of good report, virtuous, and praiseworthy.
"...looking unto Jesus, the author and finisher of our faith, who for the joy that was set before Him endured the cross, despising the shame, and has sat down at the right hand of the throne of God." (Hebrews 12:2)