Q. 31. Why is He called Christ, that is anointed?
Because He is ordained of God the Father, and anointed with the Holy Ghost, to be our chief Prophet and Teacher, who has fully revealed to us the secret counsel and will of God concerning our redemption; and to be our only High Priest, who by the one sacrifice of His body, has redeemed us, and makes continual intercession with the Father for us; and also to be our eternal King, who governs us by His Word and Spirit, and who defends and preserves us in (the enjoyment of) that salvation, He has purchased for us.
 Hebrews 1:9;  Deuteronomy 18:18; Acts 3:22; John 1:18 and 15:15; Matthew 11:27;  Psalm 110:4; Hebrews 7:21 and 10:14;  Romans 8:34;  Psalm 2:6; Luke 1:33;  Matthew 28:18; John 10:28.
Q. 32. But why art thou called a Christian?
Because I am a member of Christ by faith, and thus am partaker of His anointing; that so I may confess His name, and present myself a living sacrifice of thankfulness to Him; and also that with a free and good conscience I may fight against sin and Satan in this life: and afterwards reign with Him eternally, over all creatures.
 1 Corinthians 6:15;  1 John 2:27; Joel 2:28;  Matthew 10:32;  Romans 12:1;  Ephesians 6:11–12; 1 Timothy 1:18–19;  2 Timothy 2:12.
The term “Christ” (Greek: Christos) is not part of the name of the Lord, contrary to popular understanding. It is really the title of the Lord, meaning “anointed one.” The Hebrew for “anointed one” is “Messiah.” This means that when we talk about the Old Testament saints longing for the Messiah, we are essentially talking about their longing for Christ.
Now, in the Old Testament, there were three classes of people who could be called anointed ones. They were: (1) the prophets, thus Elisha was anointed to be a prophet by Elijah (see 1 Kings 19:16); (2) the priests, thus Aaron and his sons were anointed to the priesthood by Moses (see Exodus 28:41); and (3) the kings, thus Samuel anointed David to be king (see 1 Samuel 16:13). The Lord Jesus Christ was the long-expected Messiah who is anointed,—not with oil but with the Holy Spirit,—to all these three offices. He is the Prophet par excellence (Deut 18:18; Jn 1:1), He is Great High Priest according to the order of Melchizedek (Ps 110:4; Heb 4:14) and He is the King of kings, the Lord of lords (Isa 9:6–7; Rev 19:16). As Prophet, He reveals to us, by His Word and Spirit, the will of God for our salvation (cf. WSC 24; Heb 1:1; Jn 16:13). As Priest, He once offered up Himself a sacrifice to satisfy divine justice, and reconcile us to God, and He continues to make intercession for us at the right hand of the throne of God (cf. WSC 25; Heb 4:14; 7:25; 9:28). As King, He subdues us to Himself by His Word commanding and instructing, and His Spirit illumining and working regeneration in us. He also rules and defends us, and restrains and conquers all His and our enemies (WSC 26; 2 Cor 10:5; Mt 11:29; 2 Tim 4:18).
These things also relate to us as Christians. We are called Christians not only because we are the disciples of Christ, but because we are members of Christ by faith and therefore are partakers of His anointing. The Apostle John refers to this anointing when he says: “But the anointing which ye have received of him abideth in you, and ye need not that any man teach you: but as the same anointing teacheth you of all things, and is truth, and is no lie, and even as it hath taught you, ye shall abide in him” (1 Jn 2:27). But what is this anointing? Well, for all intents and purposes, it is equivalent to the indwelling of the Holy Spirit in the heart of every believer at the point of regeneration and union with Christ by faith. It is therefore through the anointing that believers receive all the benefits of redemption, which Christ procures for us as the Anointed Prophet, Priest and King, such as (accordingly) knowledge and faith, forgiveness and peace of conscience, victory over sin and final glorification.