A.T. Robertson Commentary John 12:16

"These things understood not his disciples at the first: but when Jesus was glorified, then remembered they that these things were written of him, and that they had done these things unto him." — John 12:16 (ASV)

Understood not (ουκ εγνωσαν). Second aorist active indicative of γινωσκω. Another comment by John concerning the failure of the disciples to know what was happening (cf. 2:22; 7:39).

At the first (το πρωτον). Adverbial accusative, as in 10:40; 19:39.

Was glorified (εδοξασθη). First aorist passive indicative of δοξαζω, to glorify, used of his death already in 7:39 and by Jesus himself of his death, resurrection, and ascension in 12:23; 13:31.

Then remembered they (τοτε εμνησθησαν). First aorist passive indicative of μιμνησκω. It was easier to understand then and they had the Holy Spirit to help them (16:13-15).

Were written of him (ην επ' αυτω γεγραμμενα). Periphrastic past perfect passive of γραφω with neuter plural participle agreeing with ταυτα (these things) and singular verb, though the plural ησαν could have been used. Note the threefold repetition of ταυτα in this verse, "clumsy" Bernard calls it, but making for clarity. The use of επ' αυτω for "of him" rather than περ αυτου is unusual, but occurs in Re 10:11; 22:16.

They had done (εποιησαν). First aorist active indicative of ποιεω, simply, "they did."