Jesus tells this parable to confront the self-righteous confidence of those who assume their wealth is a sign that God approves of them. Such an attitude assumes that a poor person's condition reflects moral inferiority and God's judgment, and it excuses a lack of concern for the beggar at the doorstep.
The rich man (no name is given, he is known only by his wealth) learns too late that his confidence in his wealth was misplaced. His first reaction was to continue thinking that Lazarus existed to confirm the rich man's opinion of himself; he requested that Lazarus serve him to reduce his suffering (v. 24).
Abraham informs him that Lazarus ("he whom God helps") does not exist simply to serve him, and that there is no travel between heaven and hell. This shocks the rich man into realizing how desperate his situation is; it is so bad that he does not want his five brothers ending up where he is (v. 27,28).
It is a terrible and sad thing to see people who have not given serious thought to their eternal welfare. The fact remains that unbelief with respect to God and His promises in Christ will condemn a person to eternal damnation (Jn. 3:36; Mt. 25:41). It is better to learn this before dying instead of after.
The rich man's request that Lazarus go back to warn his five brothers shows a lack of understanding concerning our source of spiritual instruction. "They have Moses and the prophets; let them hear them" (v. 29) is Abraham's response. All who want to know the way of salvation must pay attention to God's revelation of Himself in Holy Scripture (Ps. 119:1-5).
Jesus reinforces this when He says, "You search the Scriptures, for in them you think you have eternal life; and these are they which testify of Me" (Jn. 5;39). In other words, the Old Testament writings clearly point to our Lord Jesus and His coming from the Father in the flesh (Gen. 3:15; Is. 7:14), His anointing and perfect service (Ps. 45:7; Is. 61:1,2), His suffering for lost mankind (Is. 63:4-11; Ps. 8:4,5), and His being raised to glory (Ps. 16:10; 110:1).
Jesus is God's final revelation (Col. 2:9; Heb. 1;1,2); He is the "Word-made-flesh" (Jn. 1:14). To hear Him is to hear the Father (Jn. 14:10; Lk. 10:16). We do not look for other revelations from God concerning salvation (Jn. 14:6). After His resurrection Jesus (the critical "One" to rise from the dead) appeared only to those who would serve as His witnesses to the world (Acts 10:40-43). When Jesus prays for His Church He prays, "Sanctify them by Your Truth, Your Word is truth" (Jn. 17:17). By this prayer we each become a "Lazarus", "one whom God helps", through His Word of salvation in Christ.