'Three Days' in the Bible

Then said the king to Amasa, Assemble to me the men of Judah within three days, and be thou here present.

So Gad came to David, and told him, and said to him, Shall seven years of famine come upon thee in thy land? or wilt thou flee three months before thy enemies, while they pursue thee? or that there be three days' pestilence in thy land? Now consider, and see what answer I shall return to him that sent me.