Christ will return suddenly at an unknown hour when He is not expected. The heavens will disappear with a great noise. Everything on earth will be destroyed by fire. God will create a new heaven and a new earth.
Knowing this and waiting for our Lord's coming, we ought to live holy and godly lives. Live lives that are separated from sin and evil, set apart for God's use, and devoted to Him alone. "Holy conduct refers to action, godliness refers to attitude. Holy conduct refers to the way I live my life, godliness refers to the spirit of reverence within me by which I live my life. Holy conduct refers to that which rules my behavior, and godliness refers to that which rules my heart. And so he (Peter) is saying what kind of person ought you to be in heart and in behavior, in motive and in action, in attitude and in duty." (John MacArthur) Instead of working for things that will be destroyed, we should focus on working for/investing in things that are eternal. We need to guard ourselves against materialism and worldliness. "Since, then, you have been raised with Christ, set your hearts on things above, where Christ is, seated at the right hand of God. Set your minds on things above, not on earthly things." (Colossians 3:1-2)
"O for a heart that is willing to serve,
Laboring while it is day!
Nothing is lost that is done for the Lord,
He will reward and repay." (Unknown)
"Only one life, 'twill soon be past,
Only what's done for Christ will last.
And when I am dying, how happy I'll be,
if the lamp of my life has been burned out for Thee." (Unknown)