'Thirty' in the Bible

And he made the sea, molten, ten cubits from brim to brim, round all about; and its height was five cubits; and a line of thirty cubits encompassed it round about.

And Jehoiada grew old and was full of days, and he died; he was a hundred and thirty years old when he died.

And Josiah gave for the children of the people a heave-offering of the flocks, lambs and goats, all for the passover-offerings, for all that were present to the number of thirty thousand, and three thousand bullocks: these were of the king's substance.