The term "holiness" which appears in Hebrews 12:12 in the King James Version means sanctification. The Scripture constantly exhorts those who have been justified by faith to pursue sanctification; the process is termed a "renewing of the mind," Romans 12:2, which means a transformation of the thinking. Standards, aspirations, and priorities which characterize the thinking of man must be replaced by standards, aspirations, and priorities which are in accordance with the will of God. The man who is unwilling to conform himself to the will of the Lord God shall not see the Lord, for he shall not be among those who the Lord raises from the Dead.
The malefactor is one of two who were crucified together with Jesus. In the account, which is found in Luke 23:32-43, several things are obvious:
(1) The malefactor had repented of sin, knowing that his punishment was just. In this respect, the malefactor was like the Publican of Luke 18:10-14.
(2) The malefactor was sufficiently familiar with Jesus to know that Jesus was innocent.
(3) The malefactor had familiarity with the Gospel of the Kingdom of God and had believed the Gospel, recognizing Jesus as the anointed King.
(4) The malefactor, knowing that he would not survive the ordeal of crucifixion, demonstrated not only faith in the Resurrection, but also faith in the authority of Jesus to forgive sin and faith in the power of Jesus to raise the dead.
By the experiences of life and his embrace of the Gospel of the Kingdom of Heaven, the malefactor had become sanctified -- his thinking had been transformed; consider Psalm 51:16-17.
Passages such as Matthew 9:9-13, Mark 2:14-17, Luke 5:30-32, and Luke 15:1-7 are dripping with sarcasm. In these passages, Jesus uses the terms "the Whole," and "the Righteous," and "the Just," to refer to the self-righteous and the hypocrites, exemplified by the Pharisees and the Scribes.
The Lord God does not resurrect the Reprobate to Life Everlasting; the malefactor crucified alongside Jesus had better understanding of the things of God and greater submission to the will of God than does the typical Protestant. The malefactor was justified by faith, and he died in faith; Hebrews 11:13. On the day of the Resurrection, he indeed shall be with the Lord Jesus, in Paradise.