Proverbs 1:17

Surely in vain the net is spread in the sight of any bird.

A net spread openly in sight of a bird is spread in vain, because a trap that its intended prey can see fails to catch or deceive it.
To lead souls away and succeed, Satan must therefore deceive, and must work secretly, covertly, underhandedly and hidden, never openly and frankly.
His secret work uses deceiving influence and speech to mislead, to hoodwink and to blind, with false pretenses set forth as truth while suspicion is hidden and lulled to sleep.

He covers temptation and sin with garments of righteousness to win many to his side and lead many astray.
Under that righteous cover he holds out glorious prospects before the church and the promise of great good to be obtained by doing the very things God told them not to do.
The principles by which he worked in heaven are the same principles by which he works through human agents to deceive and corrupt the whole world from beginning to ending, so that revolters against divine government do not ascribe their disaffection to themselves and apostasy and rebellion against God come into human ranks as they came into heaven.

As the end draws near he stirs up minds in proportion to their capabilities and knowledge to sow seed that will produce an unwanted harvest, leading those who are ambitious for money and to be first and too proud to be anything but highest to murmur and complain through unconquered natural and hereditary tendencies.
He himself remains undetected while he reaps a harvest of souls through dissension and alienation and hurls charges through those he has tempted against those who would stand stiffly for the truth, proving himself a liar and a murderer from whom unwary souls must learn wisdom from God to escape.
Yet people dazzled by human speculation and false religion fail to recognize the danger before them and can walk into the snare as readily as if blindfolded, even in an age of great learning and light.