“(The Lord) Who satisfies your mouth with good things, So that your youth is renewed like the eagle’s.” Psalms 103:5
When we say the Good things that the Lord fills our mouth with, our entire self gets renewed. It’s the words that we speak, that ages us closer to the miserableness of oldness (feebleness) or keeps us young and dynamistic in His presence.
Our words come from our thoughts, so when the Lord promises to fill us with good words (that will eventually actualize as we speak), He is promising to give us thoughts of refreshment, wisdom, purity, nobleness, praiseworthy and goodness.
It’s not about speaking good words, but speaking the Words that comes to you from God. Final verdict is always given off in writing and speaking. You have a written Final conclusion over your life (His Word), let it show forth in your life by You speaking it to yourself, your situations and to the enemy who wants to see your doom.