Do not boast about tomorrow, for you do not know what a day may bring forth.
The Bible has a single verse that speaks to the issue of procrastination: "And as it is appointed for men to die once, but after this the judgment" (Hebrews 9:27). First, we are not guaranteed a long life. Second, when we die we face the judgment seat of Christ where our spiritual life will be examined (1 Corinthians 3:11-15). And third, we have a misconception about what brings joy in life. We have mistaken religion for the fruit of the Spirit (Galatians 5:22-23). To assume that we have plenty of time to "get serious" about spiritual things is to presume upon the future. To assume we won't enjoy spiritual growth is an insult to God.
If you have been procrastinating about engaging in spiritual growth, don't assume that you know the future. Redeem the time today while you are able (Ephesians 5:16).Do not so contemplate eternity that you waste today.