Yahshua is the Hebrew name of the Son of God. It is what His father Yoceph (Joseph) and His mother Miriam (Mary) called Him when He was born, as recorded in Luke 1:31 and Matthew 1:21. The footnote for this verse in the NIV New Testament reads: Jesus is the Greek form of Joshua.

In Hebrew, as in old English, there is no "J" sound, and the name is more accurately rendered Yahshua. It means "I am powerful to save," since it is constructed from Yah, the name of the Father (as in Hallelujah, "Praise Yah"), which means "I AM," and shua, which means "power and authority to save."

We call Him Yahshua because that is truly His name.

For a more in-depth discussion of His name, see the article What's In A Name?