Have a proper frame of mind is important because it is what affects how we manage our life.
There is an erroneous statement going around that at first may seem good, but when examined is actually very unhealthy for Christians. This statement goes something along the lines of “I am just a sinner saved by grace.”. Yes, it is true we are saved by grace – God’s attitude whereby He gives a benefit with consideration of merit – so we could not earn salvation; however, God does not refer to His children as sinners, but as saints.
Saints are ones who have been set apart unto God. Are we going to focus on what we were, or what we are in Christ?
I am a saint, not a sinner any more, and therefore should act as a saint.
This is not denying the fact that saint sin, even though God has provided everything we need not to sin. Rather, it is having a proper frame of mind in which we should be judging our thoughts and actions by throughout the day. Since we are saints, unrighteous thoughts and sinful actions have no place in our lives anymore.
Therefore, since we have been raised with Christ, seek the things above where Christ is seated at the right hand of God. Frame your mind on the things above, not upon the earth, for you have died and your life is hidden with Christ in God. – Colossians 3:1-3
Put to death (separate yourself from) the works of the flesh and put on who you are in Christ.
Therefore, put to death your members, which are upon the earth: fornication, uncleanliness, passions, desires lacking in character, and covetousness, which is idolatry, for which things the wrath of God comes upon the sons of disobedience, in which also you once governed the manner of your life, when you were living in them. But now you also put off these things: anger, wrath, things lacking in character, blasphemy, corrupt speech out from your mouth. Stop lying to one another, having stripped off the old man with its practices and put on as an outer garment the new man, the one being renewed unto the full experiential knowledge according to the image of its Creator. – Colossians 3:5-10