In every discussion of the Judgment that I can find recorded in the Bible, there is a separation of two very distinct groups of people. The one, the faithful children of God who have overcome the temptations of this world and have shown themselves to be pleasing to the Almighty (cf. Revelation 2:10, 2 Corinthians 5:9). The other, the unfaithful/ignorant who have either chosen to ignore the commands of God or have never been contacted with the saving grace of the Lord because of one reason or another (cf. 2 Thessalonians 1:8-10, Matthew 28:19-20). This separation can be easily seen in this life by the actions and intentions of the individual (Psalm 1), but comes to a head, if you will, at the final Judgment when Jesus will judge all nations by His word (John 12:48) by dividing the sheep and the goats (Matthew 25:31-33).
However, our most common way by which we would attempt to ascertain the salvation of another individual, which I would argue is important for us to do since we are commanded to evangelize (Mark 16:15) and build one another up through teaching (Ephesians 5:19, Colossians 3:16, Galatians 6:2, Hebrews 10:24), is normally some sort of combination of faithfulness to the worship assemblies and the overall "goodness" of the individual. The same can be said of our own understanding of our salvation! We often think that if we make it to every worship service throughout the week and do not allow ourselves to imbibe in our "pet sin" that we have been faithful that week. But, in the context of Matthew 25:31-33, when Jesus speaks of the dividing of the two groups at the day of Judgment, He doesn't use these guidelines of faithfulness.
What He does use will most likely stomp all over our toes and cut straight to our hearts. No, He doesn't use the conventional set of parameters, what He uses is our servitude to our fellow man! I'll let Him speak for Himself...
Then the King will say to those on His right hand, 'Come, you blessed of My Father, inherit the kingdom prepared for you from the foundation of the world: for I was hungry and you gave Me food; I was thirsty and you gave Me drink; I was a stranger and you took Me in; I was naked and you clothed Me; I was sick and you visited Me; I was in prison and you came to Me.' Then the righteous will answer Him, saying, 'Lord, when did we see you hungry and feed You, or thirsty and give You drink? When did we see You as a stranger and take You in, or naked and clothe You? Or when did we see You sick, or in prison, and come to You?' And the King will answer and say to them, 'Assuredly, I say to you, inasmuch as you did it to one of the least of these My brethren, you did it to Me." - Matthew 25:34-40
There it is, the Divinely given, although not exhaustive, list of the reasons one will be granted with entry into heaven at the Judgment. It's not what we normally think, is it? And yet, it is the thing that our Lord chose to use in this instance to discuss the final Day.
"People will not care how much you know about the Bible until they know how much you care about them." - Unknown
But, are we really meeting the expectations of Jesus when we are doing these small acts of giving? I'm just as guilty as anyone else in this, but I don't think so! What Jesus is discussing isn't a single instance of benevolence once or twice a month. What He's discussing is a life of helping! He's commanding a life of giving because any time we give it helps someone else, which was the reason for Him coming to earth when it is boiled down to its most basic form (John 10:10), and it shows people that His followers care.
I heard it said one time, "People will not care how much you know about the Bible until they know how much you care about them." So, remember, if you've forgotten, the Christian life is one of putting a jacket on Jesus. Not physically, but figuratively in every act of kindness done to the needy and helpless in our world. In what amounts to such a cold atmosphere, in that it is wholly given to idolatry (cf. Acts 17:16), sometimes a jacket is all that is needed.