Cruz told delegates and voters to "vote your conscience" in November and never specifically said that people should cast their ballots for the Republican nominee. During the course of his speech, Cruz only mentioned Trump once, to congratulate him on getting the nomination.
"To those listening, please, don’t stay home in November. If you love our country, and love your children as much as I know you do, stand, and speak, and vote your conscience, vote for candidates up and down the ticket who you trust to defend our freedom and to be faithful to the Constitution," Cruz said.
As he continued speaking, and the crowd began to realize that an endorsement seemed less likely, the cheers that marked the early part of the speech became boos.
"I appreciate the enthusiasm of the New York delegation," Cruz said to the vocal Trump home-state supporters who were placed right in front of the stage. They were yelling "We want Trump! We want Trump!"
Cruz's wife, Heidi, was seen leaving the arena when the booing started getting very loud. Former Virginia Attorney General Ken Cuccinelli told ABC News that he escorted Heidi Cruz out of the convention hall because “it was volatile and the Trump folks were physically approaching and confrontationally yelling,” he said via text.
"People behind her were getting very ugly, and physically approaching her and Raphael, and it was not a pretty situation," Cuccinelli told ABC. "The decision was instantly made to not talk to media and get immediately out of the arena."
"People from my own delegation were physically approaching her while yelling at her. So, I physically moved media out of her way, and got in the way of my own delegation so she could clear by and get out of the arena," he said.
The fact that Cruz spoke at all came as a surprise to some considering how bitter the primary campaign became towards the end.
At one point, Trump insinuated that Cruz's wife Heidi was less attractive than his own wife Melania, and later he made suggestions that Cruz's Cuban father was somehow connected to the assassination of President John F. Kennedy.
He also questioned whether Cruz was eligible to run for the presidency because he was born in Canada.
Shortly after Cruz exited the stage to a growing round of boos, Trump entered the arena on the opposite side to sit with his family and watch his son Eric address the crowd.
Cruz turned to Twitter to reiterate his main point, not mentioning Trump:
ABC News' Katherine Faulders contributed to this report.