31 impudent, covenant breakers, without natural affection, implacable, unmerciful.
Romans 1:31 Cross References - Living_Oracles
Matthew 15:16
16 Jesus answered, Are you also void of understanding?
Romans 1:20-21
20 (for his invisible attributes, even his eternal power and divinity, since the creation of the world, are very evident; being known by his works:) so that they are inexcusable.
21 Because, though they knew God, they did not glorify him as God, neither gave him thanks; but became foolish by their own reasonings, and their inconsiderate heart was darkened.
Romans 3:11
11 There is none that understands; there is none that seeks after God.
2 Timothy 3:3
3 without natural affection, bargain-breakers, slanderers, incontinent, fierce, haters of good men,