There are at least three possibilities: (1) Paul, formerly a student of Gamaliel, informed Luke; (2) Luke consulted a sympathetic member of the Sanhedrin, such as Nicodemus; (3) Luke received this information through divine inspiration.
Sedikit - dikitnya ada tiga kemungkinan: (1) Paulus, mantan murid Gamaliel, memberi tahu Lukas; (2) Lukas berkonsultasi dengan seorang anggota Sanhedrin yang bersimpati, seperti Nikodemus; (3) Lukas mendapatkan keterangan ini melalui ilham ilahi.