Paul writes: May the Lord direct your hearts to the love of God and to the steadfastness of Christ (2 Thess 3.5).
It is obvious that these genitive phrases are ambiguous and can be interpreted in a couple different ways. Is he speaking about the love that God has for us, or about our love for God? And does he mean that the Lord should direct our heart's to Christ's own steadfastness, or to a steadfastness of our own that is like Christ's?
In a way I think both readings of either phrase are important, because one leads to the other.
We certainly need to have love for God, but this is accomplished when we realize God's love for us. It is not easy simply to will oneself into love for another person. I am sure that we can all relate to this in our own experiences: there may have been persons who did us wrong, for whom love simply was not forthcoming. But love can be born in our hearts when we perceive the love the other person has for us. Imagine how you feel when a person is unexpectedly kind and warm towards you -- the way your heart opens up to him, and is willing to accept him, and suddenly he becomes a concern for you.
But if that is how things stand for ordinary persons and ordinary, mundane acts of kindness, how much more love ought to be born in our hearts when we realize God's love for us! God's love is not like the love of human persons; it has no limits, there is nothing which goes 'too far' for this love. It is a love that is willing to accept death in place of the beloved, so that that beloved will live. As Paul writes elsewhere, God's love for us is demonstrated in the fact that, while we were still sinners, Christ died for us (Rom 5.8).
And we certainly need to have the steadfastness of Christ, but this is something that is hard to will ex nihilo into our lives. Steadfastness in the life of a Christian means putting up with much that the ordinary person on the street would not bother resisting: temptations to various sorts of activity; the taunts and mockery of those who hate the faith; and so on. How can a person simply put up with all these things, and keep steadfast to the faith and directives given by Christ? It seems to me there is no other way except by looking at Christ, and what his steadfastness meant for us.
Heb 12.3 says: Consider him who endured such hostility against himself from sinners, so that you may not grow weary or lose heart. It was no easier for Christ than it is for us; in the case of many, their sufferings do not compare to Christ's at all. Yet Christ happily endured them for the sake of our salvation, so that we might one day see an end to our suffering. If we look at his example and see the depth of his suffering for us, how can we not gladly suffer our own tiny bit, if this is what the Lord should will? What can a few words of mockery do to me, when Christ's hands were pierced with nails and his head beaten with reeds?