Proverbs 27:1 - Boast not thyself of tomorrow; for thou knowest not what a day may bring forth.
Speaking for myself, I have lived most of my life by intentionally and unintentionally assuming so many things regarding what lies ahead. Is that considered "boasting"? Well...in some ways it is kind of arrogant to take for granted what tomorrow brings. If nothing else, it demonstrates a lack of need and dependence on God for my life. So in a passive sense, I guess it could be considered "boasting".
What I should be doing is living as though tomorrow is not guaranteed. If I'm going to assume anything, I should assume that my tomorrow in this life will never occur. If I took-on this mentality, how might things be different? Would I put off that month-old promise to take my son to the museum? Would I pass-up the opportunity to discuss "life matters" with my 12-year-old daughter at her bedside as I tucked her in. Would I tell God that today was just too busy to read His Word? Would I stay up late watching that new movie on blue-ray instead of holding my wife in bed and talking about whatever was on her mind.
These are just a few of countless decision-points that just may be different if I didn't continuously live as if tomorrow was assured. So how should I change? I will do my best to quit "boasting" of tomorrow in my subtle way. I will live in complete dependence on my Lord and Savior, Jesus Christ. I will be thankful for the abundance of mercy and grace I have received, and hopeful that my life will be pleasing to God, finding favor in His righteous will.
I will also stop ignoring the fact that people all around me are on a path toward eternity apart from God. I must acknowledge that this is the most tragic crisis mankind has ever faced and it's at our doorstep. I pray that God will give me the courage, wisdom, knowledge, understanding, and ability to point people toward salvation though Christ. I just want it to be so real that I'm incapable of ignoring it any longer. Tomorrow may never come for so many people that we know. Please join me in obeying Proverbs 27:1 and humble yourself to the realization that God holds tomorrow in His hands...not us.