The truly saved are those who pursue righteousness, love, and holiness. Such are the trademarks of the genuinely converted (1 John 2:29; John 13:35; Lev 20:26). But the righteous, loving, holiness-pursuing saints were not always like that. All of them, before conversion, had sin-infested hearts, minds, and souls. Some of them covered it all up with a pleasant exterior, others made no such attempt. Some of the great men and women of God were originally the worst among mankind.
Think of King Nebuchadnezzar. Pompous arrogance was his ways. A man of much wealth and many impressive achievements in construction, military, and kingship, this man felt justified in his pride. He boasted of his prosperity in ways that should make every sane man shudder. But God saved him, and turned his extravagant worship of self into a published worship of God. His story is found in Daniel 4.
Or think of some idol worshippers who became Yahweh-worshippers. The icon of faith, Abraham (Josh 24:2), the great-grandmother of king David, Ruth (Ruth 1:15-16), and the most solid group of believers in the NT, the Thessalonians (1 Thess 1:9), all come to mind as those who bowed down to idols before God saved them.
Certainly we can add some of the ‘obvious sinners’ to the list of the worst whom God saved. Rahab the prostitute (Heb 11:31), Manasseh the tyrant (2 Chron 33), and Saul the mass murderer (Gal 1:13), all received the mercy of forgiven sins.
It is after the calling of Matthew the ‘obvious sinner’ that Jesus spoke these words regarding salvation:
Those who are well have no need of a physician, but those who are sick. … I came not to call the righteous, but sinners.”Matthew 9:12-13