A.T. Robertson Commentary Mark 14:72

"And straightway the second time the cock crew. And Peter called to mind the word, how that Jesus said unto him, Before the cock crow twice, thou shalt deny me thrice. And when he thought thereon, he wept." — Mark 14:72 (ASV)

Called to mind (ανεμνησθη). First aorist passive indicative. Matthew 26:75 has the uncompounded verb εμνησθη while Lu 22:61 has another compound υπεμνησθη, was reminded.

When he thought thereon (επιβαλων). Second aorist active participle of επιβαλλω. It is used absolutely here, though there is a reference to το ρημα above, the word of Jesus, and the idiom involves τον νουν so that the meaning is to put the mind upon something. In Lu 15:12 there is another absolute use with a different sense. Moulton (Prolegomena, p. 131) quotes a Ptolemaic papyrus Tb P 50 where επιβαλων probably means "set to," put his mind on.

Wept (εκλαιεν). Inchoative imperfect, began to weep. Matthew 26:75 has the ingressive aorist εκλαυσεν, burst into tears.