How do we know the sin of indifference is serious?

God through Obadiah declares that 'the day of the Lord is near upon all the heathen' and states that what we do unto others, particularly those in need and suffering, will be returned unto us (Obadiah 15). Hebrews 10:30 reminds us that 'Vengeance is mine; I will repay,' emphasizing the seriousness with which God views our actions towards others. Indifference, in essence, is a failure to respond to the needs and sufferings of those around us and demonstrates a heart not aligned with God’s love and mercy.