Acts 5:35

‘And he said to them, “You men of Israel, take heed to yourselves as touching these men, what you are about to do.” ’

Thus he suggested that a little wisdom was needed here. He was clearly unsure in himself whether these men were of God or not, but appeared possibly to be leaning in their favour. So he advised caution. Perhaps these men were of God after all. Time would tell. Despite the opposition of some of them to Jesus the Pharisees tended to be the more moderate face of Judaism.