And God, being the just God that he is, will judge each one according to their works (1 peter 1:17 And if you call on the Father, who without partiality judges according to each one's work, conduct yourselves throughout your stay here in fear.)
There's a certain trap that we as Christians tend to fall into every now and again. We begin to think, "Im a good hearted 'Christian' with good morals - I'm all set..." So we then let our guard down and welcome certain sinful activities into our lives. We begin THINKING to ourselves, "Well, I know this thing isn't that good to do - but I'll just ask for forgiveness later." This is exactly what Satan wants us to think. And whenever we let ourselves do this, we're giving Satan the upper hand. The writer in Hebrews warns us in chapter 10:26 "For if we sin willfully after we received the knowledge of the truth, there no longer remains a sacrifice for sins." We can't just go about in our lives sinning and sinning just thinking that God will forgive us. It doesn't work that way.
Paul gives us this warning in 2 Corinthians 5:9-10; He says, "Therefore we make it our aim, whether present or absent, to be well pleasing to Him. For we must all appear before the judgement seat of Christ, that each one may receive the things done in the body, according to what he has done, whether good or bad."
God sees every single thing we do. He knows every thought we think. He hears every word we say. And He will judge us according to each of these things. We cannot hide from God and we cannot escape His judgement.
2 Peter 3:10 "But the day of the Lord will come as a thief in the night..."
We do not know when God will come back and bring forth judgment on mankind. In fact we have no idea. But as Christians, we must live our life with the thinking that each day could be our last - that we could be judged at any moment.
If the Lord returned right now - would you be ready?