It appears it was a vision similar to the one the disciples had on Mount Tabor.
And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an
high mountain apart, And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light.
And, behold, there appeared unto them Moses and Elijah talking with him. Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elijah.
While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him. And when the disciples heard it, they fell on their face, and were sore afraid. And Jesus came and touched them, and said, Arise, and be not afraid. And when they had lifted up their eyes, they saw no man, save Jesus only. And as they came down from the mountain,
Jesus charged them, saying, Tell the vision to no man, until the Son of man be risen again from the dead." (Matthew 17:1–9, KJV)
Thou didst ask as to the transfiguration of Jesus, with Moses and Elias and the Heavenly Father on Mount Tabor, as referred to in the Bible. This occurrence was perceived by the disciples with their inner eye, wherefore it was a secret hidden away, and was a spiritual discovery of theirs. Otherwise, if the intent be that they witnessed physical forms, that is, witnessed that transfiguration with their outward eyes, then there were many others at hand on that plain and mountain, and why did they fail to behold it? And why did the Lord charge them that they should tell no man? It is clear that this was a spiritual vision and a scene of the Kingdom. Wherefore did the Messiah bid them to keep this hidden, ‘till the Son of Man were risen from the dead,’
1 —that is, until the Cause of God should be exalted, and the Word of God prevail, and the reality of Christ rise up.(Baha’i Writings)
I believe the resurrection was a spiritual vision also.