Jesus Christ said in His Sermon on the Mount: "Judge not, that you be not judged. For with what judgment you judge, you will be judged; and with the measure you use, it will be measured back to you" (Matthew 7:1-2 Matthew 7:1-2  Judge not, that you be not judged.
 For with what judgment you judge, you shall be judged: and with what measure you mete, it shall be measured to you again.
American King James Version×). Therefore, many assume that it is wrong to pass judgment of any sort, and that all people should be allowed to do whatever they feel is right.
Strong's Concordance notes that the word translated "judge" in Matthew 7:1 Matthew 7:1Judge not, that you be not judged.
American King James Version×can also mean "condemn." What Christ was saying was that, as we are incapable of seeing a person's heart or knowing his or her relationship with God, we are not to take the place of God in making judgments about someone's motives or eternal salvation. And we should be humble, knowing our own weaknesses and sins.
However, in other sections of the Bible, Christ says very clearly, "Out of the abundance of the heart the mouth speaks" (Matthew 12:34 Matthew 12:34O generation of vipers, how can you, being evil, speak good things? for out of the abundance of the heart the mouth speaks.
American King James Version×) and "a tree is known by its fruits" (Matthew 12:33 Matthew 12:33Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit.
American King James Version×). While we cannot see hearts, we can see—and judge—actions. There are times God calls on us to discern others' actions because of their effects on us. For example, the Bible tells us to avoid angry people and those whose sins may rub off on us (Proverbs 22:24 Proverbs 22:24Make no friendship with an angry man; and with a furious man you shall not go:
American King James Version×; 1 Corinthians 5:11-12 1 Corinthians 5:11-12  But now I have written to you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a reviler, or a drunkard, or an extortionist; with such an one no not to eat.  For what have I to do to judge them also that are without? do not you judge them that are within?
American King James Version×). Hebrews 5:14 Hebrews 5:14But strong meat belongs to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.
American King James Version×tells us that the spiritually mature are "those who by reason of use have their senses exercised to discern both good and evil."
We are not to judge where a person stands with God, because we are simply incapable of doing so. But we must be able to "discern both good and evil" in the actions of ourselves as well as others in order to grow in wisdom and avoid falling into problems ourselves.
For an additional study tool, please read our booklet The New Covenant: Does it Abolish God's Law?