Next Paul described his present circumstances. Probably Paul meant that he had committed himself to visiting Jerusalem since he was sure this was what God wanted him to do even though he realized that trouble lay ahead (cf. Acts 20:3; Acts 9:16; Acts 19:21). Perhaps prophets had already revealed to him that the Jews would arrest him there (cf. Acts 21:4; Acts 21:11; Romans 15:30-31). Paul wanted to be faithful to the Lord more than he wanted to be physically safe or comfortable (cf. Philippians 1:20). [source][source][source]
"It should be noted that the Spirit did not prohibit his going, but told him what would happen when he arrived." [1][source]