90 As we contemplate the heart of Christ, the incarnate synthesis of the Gospel, we can, following the example of Saint Therese of the Child Jesus, “place heartfelt trust not in ourselves but in the infinite mercy of a God who loves us unconditionally and has already given us everything in the cross of Jesus Christ”. Therese was able to do this because she had discovered in the heart of Christ that God is love: “To me he has granted his infinite mercy, and through it I contemplate and adore the other divine perfections”. That is why a popular prayer, directed like an arrow towards the heart of Christ, says simply: “Jesus, I trust in you”. No other words are needed.
Source: Dilexit Nos (Vatican.va)