"Study to show thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth."–2 Timothy 2:15
Every true believer, not just the preacher or Bible teacher, is commanded and responsible to study, learn, and become skillful in God's Word. Some may have more time than others, but no believer has an excuse not to set some time aside to read and study God's Word. Now this would include personal study time at home, but one of the main ways believers are to study is by regular attendance to public worship where the Word of God is taught and discussed. We have our Sunday morning Bible Study where we go verse-by-verse through the Bible. We have our preaching service, and we also meet on Wednesday evening to study the Bible. Every believer, as much as possible, should make it a point to be here during these times.
Notice, that the verse does not say study in order to become approved unto God. It says "Study TO SHOW thyself approved unto God." A believer's diligence in study are not to be done to try to earn God's favor. It is to be done in the attitude of one who is already in God's favor based on the righteousness of Christ. It stands to reason that if a person loves Christ and trusts in His righteousness to entitle them to the whole inheritance of grace and glory, that person would want to learn more and more about Christ and about that great salvation. That person would want to be a skillful warrior in the army of the Savior and stand firm in the doctrine of Christ.
"A workman that needeth not to be ashamed," Any believer who remains unskillful in the word of righteousness because of a lazy, complacent attitude, ought to be ashamed of himself. Could you imagine such a person discussing the Scriptures with others, especially unbelievers, and being unqualified and deficient in the Word of God? He would and should be ashamed. Now we do not know the right interpretation of every single verse in the Bible, but we should know enough and be skillful enough to be faithful and able witnesses for Christ. We should be able to "rightly divide," correctly interpret and explain, the Word of truth. This is our privilege and responsibility.