Hard times came upon Isaac, and he made what could be considered a wise, common sense decision: he would head to where things were better. So, he started to head down toward Egypt, and God stopped him before he got there. While in Gerar, the Philistine part of Canaan, God told him not to continue to Egypt. Why? Because God's call on his life was in Canaan - the land promised to Abraham, Isaac, Jacob, and the future generations of Israel.
With God's will came God's blessing, even when it didn't seem to make sense. I wonder how many times we give up God's blessing because we want to do what seems to make sense - for our family, our future, or our goals. God will never go contrary to the principles of His Word, but sometimes His Word asks us to do difficult things --- by faith.
Faith and trust in God's word must always supersede our common sense logic. When we rely instead on our own understanding (instead of God's), we come up with heretical doctrines such as theistic evolution, modern perverted Bible versions, and sinful situational ethics.
In a practical sense, we may make ungodly moves, such as leaving the church into which God has fitly joined us (Ephesians 4:16) to pursue a safer economy or better politics. Instead of being a lighthouse in the darkness to which God has called us to make a difference, we make excuses from a "wise, common sense" perspective. Pretty soon the light is extinguished, and, living in sin apart from God's calling, we no longer see the promises of God fulfilled in our lives and future generations.
In every moment of every decision, we should seek the Lord's calling and the Lord's best. He is greater than any famine. He knows how to guide and protect.
Genesis 26:1-6, "And there was a famine in the land, beside the first famine that was in the days of Abraham. And Isaac went unto Abimelech king of the Philistines unto Gerar. (2) And the LORD appeared unto him, and said, Go not down into Egypt; dwell in the land which I shall tell thee of: (3) Sojourn in this land, and I will be with thee, and will bless thee; for unto thee, and unto thy seed, I will give all these countries, and I will perform the oath which I sware unto Abraham thy father; (4) And I will make thy seed to multiply as the stars of heaven, and will give unto thy seed all these countries; and in thy seed shall all the nations of the earth be blessed; (5) Because that Abraham obeyed my voice, and kept my charge, my commandments, my statutes, and my laws. (6) And Isaac dwelt in Gerar:"