'World' [kosmos] does not refer to the physical earth, but to the world system,the ideologies and the inhabitants of this world
The prince of the power of the air
The prince of this world
Matthew 4:3 in Greek and KJV
NAMES AND DESCRIPTIONS OF DEMONS OR SPIRITS IN THE SCRIPTURES:
Only in Luke and Acts; only six times. Ponera = evil, wicked
Principalities and powers, rulers
Akatharos = unclean, impure, foul. [About 20 times; confined to Matthew, Mark, Luke, Acts and Revelation.]
OTHER USES OF THE WORD 'SPIRIT'
'The others were hardened, as it is written: "God gave them a spirit of stupor, eyes so that they could not see and ears so that they could not hear, to this very day." '
These are the only occurrences of the word 'spirit' in association with some moral quality or some sinful quality.
While it is legitimate to generally see Satan behind all the negative qualities and the Holy Spirit as the source of all the positive qualities, it is not legitimate to understand the use of the word 'spirit' in these passages noting negative qualities to refer to an individual evil spirit that is in the believer causing the believer to sin in these specific ways. To do so would necessitate belief in a range of good spirits to be indwelling believers generating the given good qualities.
To go further and attribute any or all sins to indwelling evil spirits causing the sins has no validation anywhere in Scripture.
The specific attributes of'spirit' in these passages simply refer to the nature and quality of the human spirit of the people in question, on the one hand of those who belong to Satan, and on the other hand, of those who belong to Jesus.
1 Cor 4:21
'Shall I come to you with a whip, or in love and with a gentle spirit [KJV: 'a spirit of meekness']?'
2 Cor 4:13
'With the same spirit of faith we also believe and therefore speak'
'restore him gently [KJV and Greek: in a spirit of meekness]'
2 Tim 1:7
'For God did not give us a spirit of timidity, but a spirit of power, of love and of self-discipline.'
1 Pet 3:4
'the unfading beauty of a gentle and quiet spirit'
1 John 4:6
'recognize the spirit of falsehood'
In the context this is external to us, contrasted to the Spirit of truth, and descriptive of false teaching/teachers.