God protects us from snares, arrows, plagues, lions, adders and dragons. Even though the people all around you may be dying, god will protect you. Somehow this psalm reminds me of Kipling's If even though they aren't very similar.
This psalm, like most of them, starts off sweetly, telling us we should praise god by singing and dancing. But then, like most of them, it goes off the rails around verse 10 as the psalmist starts cursing non-believers and wishing death on them in unspecified ways. Then he turns it back to all the ways he'll be exalted: god will make his, um, horn straight, he'll have children even in old age and he'll get to see his enemies suffer.
God fixed the world in place and is mightier than the sea. Whoo-hoo?
Rather than start off nicely, this one gets right into the vengeance from the first verse. Among the things his enemies do: boast, kill widows, orphans and foreigners and claim that god can't see or hear it. But the joke is on them! God made eyes and ears, so of course he knows what people do! And he'll punish them.
Asaph manages to stay positive for the entire 11 verses of this psalm, urging us all to go out in the fields and sing and dance our praise to god.