'Thing' in the Bible

Jesus looked at him and loved him. Then he told him, "You're missing one thing. Go and sell everything you own, give the money to the destitute, and you will have treasure in heaven. Then come back and follow me."

But Jesus said, "Leave her alone. Why are you bothering her? She has done a beautiful thing for me,

But Peter kept saying emphatically, "Even if I have to die with you, I'll never deny you!" And all the others kept saying the same thing.

So they left the tomb and ran away, overwhelmed by shock and astonishment. They didn't say a thing to anyone, because they were afraid.