“After I returned to Jerusalem, I was praying in the Temple and fell into a trance” (Acts 22:17 NLT).

In Paul’s testimony to the angry crowd in Jerusalem, he told of an earlier time when he saw a vision of Jesus while praying in the Temple. The time may have been his first return to Jerusalem “three years” (Gal. 1:18) after his conversion in Damascus and time spent in Arabia. This is the only mention in Scripture of Paul’s “trance” and vision in the Temple. Although it may be the same vision he spoke of in his letter to the Corinthians (2 Cor. 12:1-4), the specific instruction from Jesus telling him to leave Jerusalem and go to the Gentiles, was not mentioned elsewhere.
At any rate, Paul described a state of “ecstasy” (Greek: ἐκστάσει, ekstasei – “trance”) while praying in the Temple of Jerusalem, where Jesus appeared to him with instructions to take the gospel to the Gentiles. The crowd had listened quietly to Paul’s testimony up until this point, but when he spoke of going to the Gentiles, they erupted in anger.
Of all the apostles, Paul’s call from Jesus was unique. Unique, not so much in content, as occasion. The other apostles had seen the resurrected Jesus in the flesh and were sent out to tell others. But the occasion(s) of Paul’s conversion and commissioning was from Jesus making special appearances after His ascension. As Paul once wrote, “Then last of all He [Jesus] was seen by me also, as by one born out of due time. For I am the least of the apostles, who am not worthy to be called an apostle, because I persecuted the church of God” (1 Cor. 15:8-9).