Charles H. Spurgeon on Psalms 119:13

With my lips have I declared all the judgments of thy mouth. The taught one of Psalms 119:12 is here a teacher himself. What we learn in secret we are to proclaim upon the housetops. So had the Psalmist done. As much as he had known he had spoken. God has revealed many of his judgments by his mouth, that is to say, by a plain and open revelation; these it is out duty to repeat, becoming, as it were, so many exact echoes of his one infallible voice. There are judgments of God which are a great deep, which he does not reveal, and with these it will be wise for us not to intermeddle. What the Lord has veiled it would be presumption for us to uncover; but, on the other hand, what the Lord has revealed it would be shameful for us to conceal. It is a great comfort to a Christian in time of trouble when in looking back upon his past life he can claim to have done his duty by the word of God. To have been, like Noah, a preacher of righteousness, is a great joy when the floods are rising, and the ungodly world is about to be destroyed. Lips which have been used in proclaiming God's statutes are sure to be acceptable when pleading God's promises. If we have had such regard to that which cometh out of God's mouth that we have published it far and wide, we may rest quite as assured that God will have respect unto the prayers which come out of our mouths.

It will be an effectual method of cleansing a young man's way if he addicts himself continually to preaching the gospel. He cannot go far wrong in judgment whose whole soul is occupied in setting forth the judgments of the Lord. By teaching we learn; by training the tongue to holy speech we master the whole body; by familiarity with the divine procedure we are made to delight in righteousness; and thus in a threefold manner our way is cleansed by our proclaiming the way of the Lord.