The means of this trial are all bitter and sweet happenings of Man...
The means of this trial are all bitter and sweet happenings of Man, including: fear, hunger, loss of property, lives, agricultural products, fear from enemies, economic siege, and taking part in Holy War himself, or by sending children and dear ones to the battle of war.
These trials were experienced in the first war of Islam (battle of Badr), and will also come forth at the time of the reappearance of the Expected Mahdi, the twelfth Imam (May Allah hasten his glad advent), for which Muslims should be prepared. The inflictions, which human beings encounter with, are usually concerned with wealth, life, children, or the fear of the loss of either of them.
The secret of mentioning 'fear', among the means of trials, first, may be that the purpose is the fear for the lack of either of those three things. It is always before the loss of the very things that one fears of losing them. Then, next to fear, hunger is pointed out, which comes into being as a result of poverty. Yet, in this respect, fasting is counted one of the examples of hunger. Loss of property has been situated in the third degree.
The loss of wealth, of course, is very bitter, especially for a rich person when he becomes poor. Then there comes the loss of life, which often occurs because of different ailments or after being wounded: in a battle-field and Holy War in the way of Allah, and so on. And, finally, the loss of fruits comes forth. Some of the commentators have rendered this loss into the death of one's child, which is the heaviest calamity.
"...but give glad tidings to the (steadfast) patient." It addresses the prophet of Islam (S) that he gives glad tidings to those people who persevere with patience in their calamities and difficulties.