Many call themselves "good" according to worldly standards, and observe in some variation of the commandments. They say, "We lead a good life". If they did not follow Jesus, what good is it? A life is only good if it leads to life eternal. Those cannot be said to lead a good life, who are either ignorant of, or willfully despise, the goal of good living.
No one can hope for eternal life, who does not know Christ, who is the life, and by that door enters into the fold. Anyone wishing to enter into the sheepfold, let them enter by the door; let them preach Christ; let them seek Christ's glory, not their own.