Can a Christian be Disobedient?

I recently preached away on the blessings of obedience. A lady challenged me afterwards.

A Christian is, by definition, an obedient human being, she rightly said. He has repented of his sin and cried out to God that he might be saved and forgiven. He owns Christ as Saviour and Lord, living now for Him, not self.

And yet, I pointed out, Christians may be disobedient in their earthly lives.

In 1 Corinthians 3:12, Paul says Now if anyone builds on this foundation with gold, silver, precious stones, wood, hay, straw, 13 each one’s work will become clear; for the Day will declare it, because it will be revealed by fire; and the fire will test each one’s work, of what sort it is. 14 If anyone’s work which he has built on it endures, he will receive a reward. 15 If anyone’s work is burned, he will suffer loss; but he himself will be saved, yet so as through fire.

Paul is saying that the labour of some is worthless; the labour of others is worthwhile and worthy of reward. Does the Lord not will us all to build in gold and silver? This is a picture of believers who are disobedient, but still saved.