Church Fathers on Luke 24:38

The report of Christ’s resurrection being published every where by the Apostles, and while the anxiety of the disciples was easily awakened to see Christ, He that was so much desired comes, and is revealed to them that were seeking and expecting Him. Nor in a doubtful manner, but with the clearest evidence, He presents Himself, as it is said, And as they thus spoke, Jesus himself stood in the midst of them.

This manifestation of our Lord after His resurrection, John also relates. But when John says that the Apostle Thomas was not with the rest, while according to Luke, the two disciples on their return to Jerusalem found the eleven gathered together, we must understand undoubtedly that Thomas departed from them, before our Lord appeared to them as they spoke these things. For Luke gives occasion in his narrative, that it may be understood that Thomas first went out from them…

Therefore I think it most natural that our Lord indeed instructed His disciples, that they should see Him in Galilee, but that He first presents Himself as they remained still in the assembly through fear.