In "Doctrinal Discussion" William Sillings writes:
In the current situation, where we are trying to apply Psalms which have been applied to the life and work of Jesus, we are having to try to fuse three horizons if we are to be both honest with the text and also glean applications for our lives today. That is, if we are to know what was originally meant by these Psalms, we need to try to get back to what the writer originally meant. Once we have done that to the best of our ability, we need to try to distinguish between what was actually in the mind of the writer and what we read into his mind with our Christian pre-understanding of what is there. Then we need to find out what the New Testament writers thought about the way these Psalms should be applied to Jesus and again differentiate between what those writers have actually written and what we read into what is on paper. Then we still have to determine how what we know about the Psalms can actually be applied to our own time and work.
Source: Studies in the Psalms: Adult Teacher's Insights, page 20.