This Psalm describes God as a shield. While a lot of Christians think this means God will prevent them from ever coming to trouble, the reality is a shield is designed as a protective device during the horrors of battle. They protect their users from swords, arrows, clubs, and various other weapons that existed at the time this Psalm was written. Shields are effectively useless outside of battle.
God, of course, is certainly not useless at any point in our lives. But just as we don't take up a shield during peace time, we tend not to take refuge in God when trouble is absent. The implication of Psalm 28:7, then, is not that God won't lead us to trouble, but that He will lead us through trouble. Trouble refines us like fire, strengthening our relationship with God in ways that a care free man may never understand.
There is a popular saying among Christians: "God will never give you more than you can handle." I've used this saying, I've heard this saying, now I want to erase it from history. It's not true. God gives you what you cannot handle so that you trust in Him to handle it. No fleshy body can withstand the thrust of a broadsword, but a well made shield will deflect it. In the same way, the apostles suffered a great deal of troubles that made them despair even of life, but the reason they gave for their suffering of this is so that they would not trust in themselves, but in God (2 Corinthians 1:8-11). They, like David, would hide behind their divine shield.
In this life, you will have troubles. Maybe few, if you're lucky. Maybe many if you're not so lucky. The world is unpredictable, to say the least. But you have an advantage that the unbelieving world does not. You have a God who raises the dead. A God who knows exactly what's best for you, and though He may not prevent you from encountering troubles, He will certainly help you through them when you abide in Him.