'Concerning' in the Bible

because they did not understand concerning the loaves, but their hearts were hardened.

And he said to them, "Elijah indeed does come first [and] restores all [things]. And how is it written concerning the Son of Man that he should suffer many [things] and be treated with contempt?

Now concerning the dead, that they are raised, have you not read in the book of Moses {in the passage about the bush} how God spoke to him, saying, 'I [am] the God of Abraham and the God of Isaac and the God of Jacob'?

"But concerning that day or hour no one knows--not even the angels in heaven nor the Son--except the Father.