The early communities were not recalling the ‘facts’ of the death of Jesus. They were about the business of making sense of it. Here it is not a question of history remembered but of prophecy historicised. They began looking for prophecies that would help them understand the social disgrace of the death of Jesus. The use of scriptural citations of Psalms (Ps. 2:1,7; 16:8–11; 22:1, 18, 22; 69:21, 30; 110:1; 132:11) and Prophets (Am. 8:9; Is. 50:6, 7; Zch. 12:10) became a shorthand way of dealing with the meaning of Jesus’ death. Source = https://www.academia.edu/67098286/The_memorable_invention_of_the_death_of_Jesus

================================================================ Keep in mind that ONLY in John's Gospel does the Roman soldier "pierce his side." Here is the text:

But when they came to Jesus and saw that he was already dead, they did not break his legs.19:34 Instead, one of the soldiers pierced his side with a spear, and at once blood and water came out.19:35 (He who saw this has testified so that you also may believe. His testimony is true, and he knows that he tells the truth.)

19:36 These things occurred so that the scripture might be fulfilled, "None of his bones shall be broken."19:37 And again another passage of scripture says, "They will look on the one whom they have pierced."

Here are the passion fulfillment texts in Mark:

14:18 Betrayal by friends Ps 41:9

14:34 A soul full of sorrow Pss 42:6, 11; 43:5

15:24 Garments divided Ps 22:18

15:29 Derision of onlookers Pss 22:7; 109:25

15:34 ‘My God, my God ...’ Ps 22:1

15:36 Vinegar to drink Ps 69:21

So, in John’s Gospel, the author introduces two brand new fulfillment texts: Ps 34:20 and Zech 12:10 [clearly misquoted so as to fit the context in John's passion story]: See https://goddidntsaythat.com/2012/11/20/the-case-of-mistaken-piercing-in-zechariah-12-10-and-john-19-37/

Now, to completely affirm how Gospel writers were keen to bring in fulfillment texts into their narrative, let's look at Matthew's Gospel. Does the "piercing his side" text find its way into your translation of Matt 27:49? Check it out. Some manuscripts have it; some don't. The suspicion is that some copyists were so influenced by John's use of Zech 12:10 that they inserted it into Matthew's Gospel that they were copying. To understand this corruption of ancient texts, see https://tyndalehouse.com/research/the-greek-new-testament/was-jesus-pierced-matthew-27/.

The early communities were not recalling the ‘facts’ of the death of Jesus. They were about the business of making sense of it. Here it is not a question of history remembered but of prophecy historicised. They began looking for prophecies that would help them understand the social disgrace of the death of Jesus. The use of scriptural citations of Psalms (Ps. 2:1,7; 16:8–11; 22:1, 18, 22; 69:21, 30; 110:1; 132:11) and Prophets (Am. 8:9; Is. 50:6, 7; Zch. 12:10) became a shorthand way of dealing with the meaning of Jesus’ death.
Source: The memorable invention of the death of Jesus

Keep in mind that only in John's Gospel does the Roman soldier "pierce his side." Here is the text:

John 19:33-37 NRSV

³ But when they came to Jesus and saw that he was already dead, they did not break his legs. ³⁴ Instead, one of the soldiers pierced his side with a spear, and at once blood and water came out. ³⁵ (He who saw this has testified so that you also may believe. His testimony is true, and he knows that he tells the truth.) ³⁶ These things occurred so that the scripture might be fulfilled, "None of his bones shall be broken." ³⁷ And again another passage of scripture says, "They will look on the one whom they have pierced."

Here are the passion fulfillment texts in Mark:

• 14:18 Betrayal by friends Ps 41:9
• 14:34 A soul full of sorrow Pss 42:6, 11; 43:5
• 15:24 Garments divided Ps 22:18
• 15:29 Derision of onlookers Pss 22:7; 109:25
• 15:34 ‘My God, my God ...’ Ps 22:1
• 15:36 Vinegar to drink Ps 69:21

So, in John’s Gospel, the author introduces two brand new fulfillment texts: Ps 34:20 and Zech 12:10 [clearly misquoted so as to fit the context in John's passion story]: See The Case of Mistaken Piercing in Zechariah 12:10 and John 19:37.

Now, to completely affirm how Gospel writers were keen to bring in fulfillment texts into their narrative, let's look at Matthew's Gospel. Does the "piercing his side" text find its way into your translation of Matt 27:49? Check it out. Some manuscripts have it; some don't. The suspicion is that some copyists were so influenced by John's use of Zech 12:10 that they inserted it into Matthew's Gospel that they were copying. To understand this corruption of ancient texts, see Matthew 27:49 Was Jesus Pierced before His Death?.