"Who shall separate us from the love of Christ? Shall tribulation, or distress, or persecution, or famine, or nakedness, or danger, or sword? In all these things we are more than conquerors through him who loved us."
Nothing can separate us from God's love! We must be careful not to believe that nothing bad or tough will ever happen to Christians; that isn't what Paul is saying here at all. We are promised that bad things things will happen to us, but we are also promised that none of them, no matter how horrible they are, will EVER remove us from God's hand. This promise should be enough to sustain us, yet we constantly look for something else. We are rarely satisfied in God's love alone. But we were made for Him, not this world or its pleasures. Having our eyes fixed on bringing Him glory no matter the situation will always result in joy because our joy doesn't come from anything around us; it only comes from Him. Happiness can leave us for a moment, but our joy is deeply-rooted in Christ and can't be taken.