And they knew it was he that sat for alms
The Syriac version renders it, "they knew him to be that beggar that sat daily and asked alms". As he was daily brought thither, and had, for many years, it is very likely, sat there to ask alms of the people as they went into the temple; he was well known by them, and they had but just now passed him, and observed him in the same condition he had for a long time been, and knew him to be the same. It was a clear and indisputable point with them.
At the beautiful gate of the temple (See Gill on Acts 3:2).
And they were all filled with wonder and amazement at that which had
happened unto him;
that he should have a cure so suddenly, and in such an extraordinary manner; they wondered at the power of God, which was seen in it, and that he should make use of such mean and contemptible persons as the apostles were.