A.T. Robertson Commentary Luke 9:26

"For whosoever shall be ashamed of me and of my words, of him shall the Son of man be ashamed, when he cometh in his own glory, and [the glory] of the Father, and of the holy angels." — Luke 9:26 (ASV)

Whosoever shall be ashamed (ος αν επαισχυνθη). Rather,

Whosoever is ashamed as in Mr 8:38. The first aorist passive subjunctive in an indefinite relative clause with αν. The passive verb is transitive here also. This verb is from επ and αισχυνη, shame (in the eyes of men). Jesus endured the shame of the cross (Hebrews 12:2). The man at the feast who had to take a lower seat did it with shame (Luke 14:9). Paul is not ashamed of the Gospel (Romans 1:16). Onesiphorus was not ashamed of Paul (2 Timothy 1:16).

In his own glory (εν τη δοξη αυτου). This item added to what is in Mr 8:38; Matthew 16:27.