How do I answer a Jehovah's Witness about the Trinity?

Begin with the biblical foundation: there is one God, and the Father, Son, and Holy Spirit are distinct persons who possess the one divine nature. Catholics do not believe in three gods.

State the doctrine clearly. The Trinity means one God in three divine persons. The Father is God, the Son is God, and the Holy Spirit is God. The Father is not the Son, the Son is not the Holy Spirit, and the Holy Spirit is not the Father. They are not three parts of God or three temporary roles. Each person is fully God, equal in divinity and eternity (CCC 253-255).

Show Christ's divinity. Jehovah's Witnesses identify Jesus with the created archangel Michael. Scripture instead teaches that the eternal Word is God and that everything created came into being through Him (Jn 1:1-3). If all created things came through the Word, the Word cannot belong to the class of created things. Thomas addresses the risen Jesus as “My Lord and my God,” and Jesus accepts the confession (Jn 20:28). The Son shares the Father's glory before the world existed (Jn 17:5), forgives sins (Mk 2:5-12), receives worship (Mt 14:33), and sustains all creation (Col 1:16-17).

Jehovah's Witnesses often cite “the firstborn of all creation” (Col 1:15). In biblical usage, firstborn can signify rank and inheritance, not that someone was the first creature made. The following verses explain the title: all things were created through Christ and for Christ, and He is before all things (Col 1:16-17).

Show the Holy Spirit's personhood and divinity. The Holy Spirit teaches, sends, speaks, and can be grieved (Jn 14:26; Acts 13:2; Eph 4:30). Peter tells Ananias that lying to the Holy Spirit is lying to God (Acts 5:3-4). An impersonal force does not speak, command, teach, or receive lies. At Baptism, Jesus commands one baptism in the singular “name” of the Father, Son, and Holy Spirit (Mt 28:19).

Answer patiently. The word Trinity was developed to summarize biblical truth, just as other theological terms clarify what Scripture teaches. The Councils of Nicaea in 325 and Constantinople in 381 defended this apostolic faith against claims that the Son or Spirit was a creature. They did not create a new God.

Read the passages together and ask simple questions: Is Jesus created if every created thing came through Him? Why does Thomas call Him God? How can the Holy Spirit speak and be lied to? Keep the conversation centered on Christ, without mockery or hostility.