“water canals.” The Hebrew word can also mean “streams,” like the streams of water that flow from a spring. However, in this case the word more likely means “canals” or “channels” and compares Yahweh to a farmer or landowner who channels the water running across his land as it pleases him.
“he turns it wherever he delights.” This sentence cannot be understood apart from the whole Word of God, which makes it clear that people have free will. God cannot just “turn our hearts” if we do not want them turned. Thus this verse speaks to the fact that we must look to God for guidance and be willing to allow Him to direct us.
There are dozens of places in the Bible where kings disobey God and do horrific things. There is a long list of the kings of Israel and Judah of whom it is specifically stated that they “did evil in the sight of the Lord.” Solomon was one (1 Kings 11:6). So were Nadab (1 Kings 15:25-26), Baasha (1 Kings 15:33-34), Ahab (1 Kings 16:30), Ahaziah king of Israel (1 Kings 22:51-52), Jehoram (2 Kings 8:16-18), Ahaziah king of Judah (2 Kings 8:26-27), Jehoahaz (2 Kings 13:1-2), Jehoash (2 Kings 13:10-11), Jeroboam II (2 Kings 14:23-24), Zechariah (2 Kings 15:8-9), Menahem (2 Kings 15:17-18), Pekahiah (2 Kings 15:23-24), Pekah (2 Kings 15:27-28), Hoshea (2 Kings 17:1-2), Manasseh (2 Kings 21:1-2; 2 Chron. 33:1-2), Amon (2 Kings 21:19-20; 2 Chron. 33:21-22), Jehoahaz (2 Kings 23:31-32), Jehoiakim (2 Kings 23:36-37; 2 Chron. 36:5), Jehoiachin (2 Kings 24:8-9; 2 Chron. 36:9), and Zedekiah (2 Kings 24:18-19; 2 Chron. 36:11-12; Jer. 52:1-2).
If God was making those kings do evil and turning their hearts away from Him, then He would be fighting against Himself because He also commands us to come to Him, obey His Word, and live righteous lives. God is not the author of confusion, and a kingdom divided against itself cannot stand. The very definition of “evil in God’s sight” is that it refers to thoughts and actions that are contrary to the will of God. But if God is the cause behind a king’s (or any person’s) evil thoughts and actions, then the person would not be doing that which was “evil in the sight of the Lord,” he would be doing the will of God—what God wanted him to do; and by definition, obeying the will of God is not doing evil.
So we see that Proverbs 21:1 is a true “proverb” in that it speaks of something that is ideally true or sometimes true, but it does not refer to a universal truth—something that is always true. It is similar to many of the proverbs in the Bible; for example, Proverbs 22:6 says, “Train up a child in the way he should go, and when he is old he will not depart from it,” yet we know there are good parents whose children turned away from God. Proverbs are generally true, but not always true. God can direct a king’s heart, and our hearts, if we are open to His guidance.