Whether Thomas had ever, since they all forsook our Saviour in the garden and fled, returned again to a communion with the rest, or was absent through some occasion, is not said; but upon this some have started a question, Whether Thomas, being absent, received the Holy Ghost at this time as the rest did? Some think he did not, because of his unbelief. Some of the ancients think he did; for, Numbers 11:26,27, when God gave out the Spirit to the seventy elders, Eldad and Medad, though absent, had their share of it, Numbers 11:27. The matter is not much.
Related Commentaries of John 20:24
John 20:24
24 But Thomas, one of the twelve, called Didymus, was not with them when Jesus came.