Charles H. Spurgeon on Psalms 49:3

My mouth shall speak of wisdom. Inspired and therefore lifted beyond himself, the prophet is not praising his own attainments, but extolling the divine Spirit which spoke in him. He knew that the Spirit of truth and wisdom spoke through him. He who is not sure that his matter is good has no right to ask a hearing. And the meditation of my heart shall be of understanding. The same Spirit who made the ancient seers eloquent, also made them thoughtful. The help of the Holy Ghost was never meant to supersede the use of our own mental powers. The Holy Spirit does not make us speak as Balaam's ass, which merely uttered sounds, but never meditated; but he first leads us to consider and reflect, and then he gives us the tongue of fire to speak with power.