What does Proverbs 16:10 mean?

Obligations are often phrased as statements. This is commonly seen in contracts and other legal documents. When a contract says, "the owner maintains a safe property," it is setting an expected standard, not predicting what the owner will do. The same is true of this proverb: a king acting as he should does not sin through his decrees or judgments. Kings of Israel were initiated into office by the anointing of oil. This represented the power of the Holy Spirit. A king was considered one of God's representatives on earth. As such, when he spoke, he was morally obligated to speak truthfully. When he offered judgment—a ruling, a decree, or some other decision (1 Kings 3:28)—he was expected to so righteously, and not in sin.

When Solomon was a young man, he wanted to judge the people of Israel righteously. According to 1 Kings 3:3, "Solomon loved the LORD, walking in the statutes of David his father." When the Lord appeared to Solomon in a dream at Gibeon, He asked Solomon what gift he wanted. Solomon acknowledged that God had made him king in place of his father David (1 Kings 3:7). He also acknowledged that he was inadequate to judge the nation (1 Kings 3:8). Therefore, he asked the Lord for "an understanding mind to govern your people, that I may discern between good and evil, for who is able to govern this your great people?" (1 Kings 3:9). The Lord granted Solomon's request and enabled him to render righteous judgments.