But what about the moral pollution? Can we meet the challenge that this represents? Yes, we can. How? Basically by guarding our hearts and exercising self-control.​—Prov. 4:23.

Discussing man’s relation to his environment, the late Dr. Alexis Carrel, Nobel Prize-winning biologist, in his book Man, the Unknown states: “Each individual has the power to modify his way of life, to create around him an environment slightly different from that of the unthinking crowd. He is capable of isolating himself in some measure, by imposing upon himself certain [physical] and mental disciplines . . . of acquiring mastery of his body and mind.” Yes, men have a natural ability to shut out from their minds certain things surrounding them. But this natural ability is not enough. One needs the aid of God’s Word of truth and his spirit to overcome in a bad moral environment. This is vital to the Christian who is in the world but not a part of it.

Of course, as far as it is possible, it is in the Christian’s interests to stay away from or leave an environment hostile to his spiritual well-being. ‘Bad associations do spoil useful habits.’ Wisely God’s Word counsels: “Do not have companionship with anyone given to anger; and with a man having fits of rage you must not enter in, that you may not get familiar with his paths and certainly take a snare for your soul.”​—1 Cor. 15:33; Prov. 22:24, 25.

But a Christian may have to earn his living by working alongside such kinds of people. And nearly all Christian youths are thrown in close touch with bad associations in school. Then again, a Christian man or woman may have an unbelieving mate who is selfish if not also immoral. All such comprise the environment of Christians and are a real challenge.

Or a Christian’s environment may be extremely immoral. Those about him at his place of employment or at school may be using obscene speech, be telling filthy stories. How can he successfully meet this challenge? Certainly not by sharing in such talk, being amused by it, nor by giving it a curious ear. Again God’s Word gives good advice, saying: “Keep on making sure of what is acceptable to the Lord; and quit sharing with them in the unfruitful works that belong to the darkness, but, rather, even be reproving them.”​—Eph. 5:10, 11.