In a recent comment to Bob Burney's excellent article "Are We Reaching the Lost, or Rearranging the Chairs," reader '2centsworth in the midwest' asserts that the doctrine of the Trinity is not a Biblical doctrine, though (s)he offers no Biblical evidence.  This is a spiritually fatal error, so please allow me to of offer Biblical evidence in support of the Trinity. 

Jesus clearly claimed to be God and His opponents clearly understood this.  Here are several examples.

In Jn 10:30, He said "I and the Father are one."   When subsequently asked by Jesus why they were attempting to stone Him, the Jews replied "because you a mere man claim to be God." Jn 10 33b.

In Jn 8, in response to the question "Who are you?" Jn 8:25a, Jesus replied "I Am", (borrowing from God's naming Himself I Am in Ex 3:14-15).  He did this in Jn 8:28,58. Upon doing so, the Jews attempted to stone Him (again).  Why?  They understood Him to claim to be God.  Note also that by naming Himself I Am (a form of the verb 'to be', that speaks to essence or being), God reveals something unique about His own character, that is His power of being in Himself, or His self-existence. Jesus claims this same power in John 5:26.  He says: "For as the Father has life in himself, so he has granted the Son to have life in himself."  "Life in Himself" here means self-existence, and thus eternality.  So, completely unlike the created who are dependent on God for existence, Jesus claims the power of self-existence - He is eternal.  We, the created, are not self-existent, only God is.

In Mark 2, Jesus before healing a paralytic who was brought to Him says: "Why are you thinking these things? Which is easier: to say to the paralytic, 'Your sins are forgiven,' or to say, 'Get up, take your mat and walk'? But that you may know that the Son of Man has authority on earth to forgive sins . . . ." He said to the paralytic, "I tell you, get up, take your mat and go home."  Mark 2:8b-11.  The Jews thought His claim to be able to forgive sins to be blasphemy because only God can forgive sins (Mark 2:7).  Jesus knew that the Jews believed that illness or infirmity was the direct result of sin (see Jn 9:1-3) and thus could not be healed without first forgiving the sin that lead to the infirmity.  Thus He healed the paralytic (much harder than merely saying your sins are forgiven), and in doing so, demonstrated His power over infirmity, which they understood to result from sin and thus proved His authority to forgive sin.  There are numerous other instances of Jesus claiming to be God.  He did so however in terms that 1st century Jews understood, but 21st century Westerners often miss.

Others in the Bible claim Jesus is God too.  Here are a few instances.

Thomas:

Thomas said to him, “My Lord and my God!”  John 20:28  Note that unlike other cases where spiritual beings are confused with God, Jesus does not reject Thomas' worship of Him as God. Contrast this with the how the angel reacts to John in Rev 19:9-10.

John:

"In the beginning was the Word, and the Word was with God, and the Word was God."   John 1:1

"The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the One and Only, who came from the Father, full of grace and truth." John 1:14  Thus the Word Who was God (v1) became flesh (v14).

Peter:

“Simon Peter, a servant and apostle of Jesus Christ, To those who through the righteousness of our God and Savior Jesus Christ have received a faith as precious as ours:” 2 Pet 1:1

Paul:

"while we wait for the blessed hope – the glorious appearing of our great God and Savior, Jesus Christ,"  Titus 2:13

"For in Christ, all the fullness of the Deity lives in bodily form"  Col 2:9

"Your attitude should be the same as that of Christ Jesus: Who being in very nature God, did not consider equality with God something to be grasped but made Himself nothing, taking the very nature of a servant, being made in human likeness"  Phil 2:5-7

Thus Scripture clearly attests to the Deity of Christ.

Now, on to a less critical error made by '2cents'.  In the book of Acts, we see the church often meeting in homes, but we also see larger groups of Christians gathering in other forums.  In Acts 3 & 4, it seems the prefered place was the temple courts.  In Acts 19, Paul preached and taught daily in the Hall of Tyranus for 2 years (Acts 19:9b-10).  Later in Acts 20, Paul is preaching in a (at least) 3 story building (see Acts 20:7-11, esp v9b).  This was also most probably not an individual's home.

From these Biblical teachings, you can see that 2cents' teachings are infected with gross error and should not be given any weight as they carry no Biblical authority.

Finally, I offer that 2cents' approach is to compromise on the esesntial doctrine of the Trinity in order to convert Muslims and Jews to Christianity because the Trinity is offensive to them.  I submit however, that Paul says that it is Christ crucified that is the offense (1Cor 1:23) and that to compromise on any essential doctrine of the faith is to preach another gospel, to which Paul (and any true Christian) would say "let him be anathema" Gal 1:6-10.