When was the Christian "Church" started?
The English word "church" is transliterated from two
Greek words: "Kristos" (Christ) + "Oikos" (house), or
"House of Christ." Therefore—contrary
to usage in the phone book’s Yellow Pages—the word “Church”
can only mean Christian Church.
Christ Himself is the founder of the church (Matt. 16:18). But the church did not start until the Day of Pentecost.
Here are the reasons:
was still future in Matthew 16:18 ("I will build my church");
first members were those "baptized by the Holy Spirit"
12:13), and that event was still future in Acts 1:5.
Acts 11, that event was described as already occurred
had occurred on the day of Pentecost in Acts 2.
following Logical Deduction—
Since Spirit-Baptist = Into Body of Christ
And Spirit-Baptism = At Pentecost
of Christ = At Pentecost