John Gill Commentary Psalms 49:4

"I will incline mine ear to a parable: I will open my dark saying upon the harp." — Psalms 49:4 (ASV)

I will incline mine ear to a parable
In which way of speaking the doctrines of the Gospel were delivered out by Christ, (Matthew 13:3Matthew 13:35) . Wherefore the prophet, representing his apostles and disciples, signifies that he would listen thereunto, that he might attain to the knowledge thereof, and communicate it to others;

I will open my dark saying upon the harp ;
the enigmas, riddles, and mysteries of the Gospel, being understood by the ministers of it, are opened and explained in a very pleasant and delightful manner; they are made clear and evident, and are as a lovely song upon a harp; see (Ezekiel 33:32) .