The scribes and the Pharisees with hostile eyes ‘watched him.’ That refers to a formal accusation; they wanted to bring charges against him, to have him arrested and dealt with.
Unbelievers look for ways to trip up God, to find fault with his people, to find contradictions in his word. They use all their skill to do this, and Christ disciples must therefore be wise as serpents, although harmless as doves. We should expect opposition to come and not think that it is some strange thing that happens to us. This hostility is motivated not by a love of truth – though that is often the claim – but by a cluster of sensibilities that centre around protecting a troubled conscience.