The Septuagint rendering of the latter part of the verse above is more enlightening. It didn’t just say you’d have good success; rather, it goes on to say you’ll become perceptive. The Greek word used is “suniemi”; it means to be sagacious and perspicacious; to have high intelligence; to have your thinking level elevated to a high class! It also means to be acutely insightful, possessing the ability to “mentally put things together.” That’s what the Word of God does in your life. It makes you wise and penetratingly discerning.
The Amplified version says, “...you shall deal wisely and have good success.” Meditating on the Word makes this happen for you. You become excellent in your dealings with people, in business, in your finances, etc. The Spirit of God, through the Word, brings extraordinary sagacity into your life. Every Christian needs this. Psalm 119:98 says, “You, through Your commandments, make me wiser than my enemies; for they are ever with me.”
The Word makes you wiser than your adversaries. Then Psalm 119:99-100 says, “I have more understanding than all my teachers, for Your testimonies are my meditation. I understand more than the ancients because I keep Your precepts.” His testimonies are His declaration of Himself: What He said about Himself, about us, and about His kingdom. As you meditate on all that, your mindset is elevated to make accurate decisions and choices. Everything you do will turn out excellently.