1 This is now, beloved, the second letter I am writing to you in which I am stirring up your sincere mind by way of reminder, 2 that you should remember the words spoken beforehand by the holy prophets and the commandment of the Lord and Savior spoken by your apostles. 3 Know this first of all, that in the last days mockers will come with their mocking, following after their own lusts, 4 and saying, “ Where is the promise of His coming? For ever since the fathers fell asleep, all continues just as it was from the beginning of creation.” 5 For when they maintain this, it escapes their notice that by the word of God the heavens existed long ago and the earth was formed out of water and by water, 6 through which the world at that time was destroyed, being flooded with water. 7 But by His word the present heavens and earth are being reserved for fire, kept for the day of judgment and destruction of ungodly men. 2 Peter 3:1-7 NASB
The Word of God is filled with references to testing and proving. During our Lord’s ministry his enemies asked him tough questions in order to “test” him. Jesus ordered lepers whom He had healed to show themselves to the Priests to “prove” that they were no longer unclean. God puts our Lord’s disciples through fiery trials in order to “test” their faith and “prove” their authenticity. God does not change. He is immutable. His ways do not change either. He still puts those who profess to be Christians to the test. This proving is not for his knowledge however. He knows all already. The proving is for our sake.