Q: Please clarify the three words designating God's wills.
A: God's decretive will is that which God has willed to come to pass through either His decrees, or His sovereignty, and His predestination. In this case, whatever He has decreed to come to pass will definitely come to pass; nothing can keep it from coming to pass. His efficacious will is perhaps only a facet of His decretive will; but it emphasizes the fact that God will effect or cause those things He wills to come to pass. In both the decretive and efficacious wills, God is directly responsible for causing His will to come to pass. As to God's permissive will, this is something God allows to come to pass, even though it may be contrary to His moral will. The entrance of sin falls into the realm of God's permissive will. This would be something He permits to happen but did not effectively or efficaciously cause to happen; therefore, He is not directly responsible.
Q: How does a believer determine what God's will is when making decisions?
A: We already know God's moral will: it is whatever God has commanded us to do. In those areas about which God has spoken in Scripture, we do not have to pray to see if we should do it or not. God's moral will is fully revealed in the Bible. The believer's responsibility is obedience (I Corinthians 7:19).
In areas where the Bible gives no command or principle, areas that are non-moral or neutral, the believer is free and responsible to choose his own course of action. Any way you decide is fine with God. Any decision made within the moral will of God is acceptable to God. Where God has spoken, we obey; where God has not spoken, we are responsible to make that choice. In non-moral decisions, the goal of the believer is to make wise decisions on the basis of spiritual expedience; that is, on the basis of wisdom.
In all decisions, the believer should humbly submit in advance to the outworking of God's sovereign will as it touches that decision. God's sovereign will is His secret plan that determines everything that happens in the universe. When making a decision, three things should be considered. First, God's sovereign will does not exclude planning. It requires humble submission, but does not exclude planning (James 4:13-16). Second, circumstances define the context of the decision, but circumstances must be weighed by wisdom and not read as road signs to God's individual will (Philemon 15-16). Third, so-called “open doors” are God-given opportunities for service, but this does not mean they are specific guidance from God requiring you to enter. Open doors are opportunities, but you can make the decision to enter one way or the other. This is brought out by I Corinthians 16:8- 9; and Colossians 4:3, which emphasize the availability of service. In II Corinthians 2:12-13, we read how Paul had an open door, but he chose to walk away from it. Open doors do not mean you have to enter them.