This can be stated in active form. Alternate translation: "but I was a student of Gamaliel here in Jerusalem" (See: [[rc://en/ta/man/jit/figs-activepassive]])
Here "feet" stands for the place where a student would sit while learning from a teacher. Alternate translation: "by Gamaliel" (See: [[rc://en/ta/man/jit/figs-metonymy]])
This can be stated in active form. Alternate translation: "He instructed me how to carefully obey every law of our forefathers" or "The instruction I received followed the exact details of the law of our forefathers" (See: [[rc://en/ta/man/jit/figs-activepassive]])