David was both the greatest king of ancient Israel and one of its greatest theologians as well. We see this illustrated in Psalm 139:1–12, which contains some of the most significant teaching on God’s omniscience and omnipresence in all of Scripture.
We see in vv. 7–12 a focus on divine omnipresence, which means that God is present everywhere in His creation. As David writes, there is no place where we can hide from the Lord. When he asks where he can flee from the presence of the Creator (v. 7), the answer expected is “nowhere,” a truth Jonah learned the hard way when he attempted to run away from God (Jonah 1–2). From the highest heights to the lowest depths, from land to sea—we can never get away from the Lord. Moreover, God’s omnipresence does not mean that part of Him is present here and part of Him is present there. He is fully present everywhere in the universe, though He does not make His presence felt as strongly in some places as He does in others. For example, under the old covenant, God was no less present in Assyria than He was in the tabernacle and temple. Nevertheless, He made His presence felt in Israel’s sanctuary in a special way that He did not make it felt elsewhere (Ex. 40:34–38; 2 Chron. 7:1–3).
Verses 1–6 emphasize divine omniscience—the fact that God knows everything. In the psalm, the Lord’s knowledge is depicted in personal, intimate terms. He is thoroughly acquainted with all of David’s ways. His knowledge extends even to the future—before David speaks a word, our Creator knows what He will say (vv. 1–5).
John Calvin issues a warning to us in his commentary on today’s passage: “Many when they hear God spoken of conceive of him as like unto themselves, and such presumption is most condemnable. Very commonly they will not allow his knowledge to be greater than what comes up to their own apprehensions of things.” We must not think of the Lord’s knowledge as being of the same kind as ours. Divine omniscience does not mean merely that God knows a whole lot more than we do. Yes, the quantity of God’s knowledge is greater than ours, but His knowledge is also qualitatively different from ours. For example, our knowledge is not determinative of reality. Our knowing that apples are red does not make them red. The Lord’s knowledge, however, does determine reality. Divine foreknowledge with respect to salvation illustrates this. When Paul says God foreknew those whom He would justify (Rom. 8:29), He means that the Lord determined whom He would justify.