We have an obligation to advise others ( St. Nicodemos the Hagiorite )

There are people who make excuses and utter the following cold and indifferent words: “Why should I be concerned with what other people do?
... Why should I advise and correct another person? I am not responsible for him!
” Such people must realize that they are obliged by the natural law, the ethical law, the Gospel, and the invisible warfare (which their fellow brothers in Christ are experiencing) to be concerned for others.
Let us listen to the divine St. John Chrysostom
who reproves such people with his golden and sweet words. He says that no one should speak in this manner because such statements are demonic and characteristic of the callousness of the devil; and Christians have no ties and nothing in common with the devil, whereas they have numerous things in common with their brothers in Christ.
“Do not utter this chilling phrase, ‘What concern is it to me? I have nothing to do with him’ ... for this is a satanic saying. It is diabolical cruelty.
It is only with the devil that we have nothing in common, whereas with all human beings we have much in common.”
Furthermore, he advises us to be concerned for the salvation of our brothers because when we look after the salvation of others we simultaneously attend to what is beneficial for us.
“Do not utter that phrase replete with gross insensitivity, ‘What concern is it to me? I have my own affairs to worry about.’ For it is precisely then that you care about your own affairs, when you seek the advantage of your neighbor. This is why St. Paul said, ‘Let no one seek his own, but each one the other’s well being’(Cor. 10:24).”
Elsewhere, he censures them who make excuses
by pointing out that the statement many people make, “It’s none of my business,” was first
voiced by Cain who murdered his own brother. He continues to say that such remarks give rise to all the evils, and he posses the following question: If the salvation of your fellow Christian is of no concern to you, to whom is it a concern? To them who do not believe in God?
To the idolaters who rejoice when they see Christians sinning? Or to the devil who struggles to destroy and throw Christians into sin?

“Do not say to me, ‘What do I care? Fear him who first uttered these words.
The statement ‘Am I my brother’s keeper?’ (Gen. 4:9) expresses the same meaning. This is from where all the evils sprout forth; for we consider the wounds of our body to be something foreign. What are you saying? You do not care about your brother? Who will care about him? The unbeliever
, who gloats over him, upbraids him, and insults him? The devil, who impels him to sin and trips him up?” 

St. Nicodemos the Hagiorite

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