'Thirty' in the Bible

And the days which we have walked from Kadesh-Barnea until that we have passed over the brook Zered, are thirty and eight years, till the consumption of all the generation of the men of battle from the midst of the camp, as Jehovah hath sworn to them;

And the sons of Israel bewail Moses in the plains of Moab thirty days; and the days of weeping and mourning for Moses are completed.