3:19 the condemnation. The word “condemnation” (Greek krisis) is also translated “judgment,” but only a judgment concluding in condemnation. The use of the definite article—“the condemnation”—emphasizes that judgment is not because of sin, but because of rejection of God’s provision of salvation from sin through the light of Jesus Christ.
3:19 men loved darkness. See also John 1:9; II Corinthians 4:3-4; Ephesians 4:13-14.
3:21 doeth truth. One who truly desires light and truth will not only believe the truth, but do the truth (contrast I John 1:6) for Jesus Christ is the Truth (John 14:6).