‘And the four angels were loosed who had been prepared for the hour and day and month and year, that they should kill the third part of men.'
God's timing is always exact. Here it is fixed with computer like precision, to the very hour, with the aim of releasing on the earth at that point in time four murderous angels who had been prepared for this very purpose. Their aim was the slaughter of ‘the third part of men', in other words a sizeable minority. There is only one definite article with respect to ‘the hour and day and month and year', stressing that the four elements of time must be seen together as indicating the defining moment, detailed step by step. They are to have their hour. The slaughter is to be considerable, ‘the third part of men' in that region. We are not told how long they would be operating. The aim was rather to bring out the evil forces at work against the world, and to bring out that God had them under control, only allowing their release on His timing.
The area in question has always been noted for its bloody wars. In John's day the Parthian menace lay beyond those borders, ever threatening the security of the Roman Empire. Later it would be the centre of the hordes of Islam, and they continue today with different Muslim nations ever active in bloodshed, whilst the whole restlessness of the area makes it a growing threat as they develop nuclear weapons and germ and chemical warfare and suicide terrorists. It has erupted again and again with horrific consequences. It is constantly erupting today. Thus the area of the River Euphrates has regularly produced something like this, and we can see in it the activity of Satanic forces.
But as this second woe (and sixth trumpet) is connected with Chapter s 10 & 11 which deal with the last days of the age and the summing up of God's purposes, it may well be seen as an intensification of the fifth trumpet occurring in the final period leading up to the end (compare the sixth seal and the sixth bowl, both precursors of the end).