Galatians 3:9

faithful The original word, like its English equivalent, may mean either trustworthy or trusting, deserving confidence or exercising it. In the former sense it occurs 1Co 1:9; 1 Corinthians 4:2. In the latter (which is the sense here), John 20:27, where it is rendered -believing". The context will determine which meaning is to be assigned to it. A similar ambiguity attaches to such English words as pitiful, mournful, hopeful.