According as his divine power hath given unto us all things that pertain unto life and godliness, through the knowledge of him that hath called us to glory and virtue: Whereby are given unto us exceeding great and precious promises: that by these ye might be partakers of the divine nature, having escaped the corruption that is in the world through lust. (2 Peter 1:3-4 KJV)
Whereby are given to us exceeding great and precious promises. Whereby what? The answer is in the previous line: Through the knowledge of him that hath called us to glory and virtue. Where do we get that knowledge of him? We get it in God's Word the Bible. This is why Bible reading and study and sitting under the preaching of the Word are so important!
Many churches have left the teaching of doctrine and the deep truths of Scripture and replaced it with music, drama, interpretive dance and a whole host of other things. The preaching of the Word gets relegated to a mere 15 to 20 minute warm fuzzy topical devotional or a text is read and then high-jacked to guilt people into getting involved in all the various programs of the church. It's no wonder people don't know what the Bible teaches and fall for things like "Judge not that ye be not judged" taken out of context and used to promote tolerance.
Christians need to get serious about the study of God's Word and demand that their pastors preach the great doctrines of Scriptures or go find a church that will. It's only in God's Word, the Bible, that we can take hold of the great and precious promises of God and take advantage of the "all things" that God's power has given us for life and godliness. If we don't know what God has said about how to be godly, how can we be godly? If we don't know the promises of God in His Word, how can we find comfort in times of need? Pastors who don't preach the whole counsel of God do a disservice to their congregation.
Also, Christians who don't study their Bibles at home are doing themselves a disservice by making themselves vulnerable to false teaching. We need both the preaching and the private Bible study, because God has commanded it in Scripture. Christians who refuse to align themselves with a church and sit under the preaching of God's Word on a regular basis are in disobedience to Hebrews 10:25 and ignore the clear teaching of the importance of preaching in the entire book of Romans. Christians who do not study the Bible privately are in disobedience to 2 Timothy 2:15.
The great and precious promises of God are largely ignored by many Christians today simply because they do not see the need to attend church, sit under good preaching and study the Bible themselves at home. It's a sad commentary on our times.