'Gain' in the Bible

for fear Satan should gain an advantage over us. For we are not ignorant of his devices.

Receive us: we have injured no one, we have ruined no one, we have made gain of no one.

We do not exceed our due limits, and take credit for other men's labours; but we entertain the hope that, as your faith grows, we shall gain promotion among you--still keeping within our own sphere--promotion to a larger field of labour,

Did I make a gain of you by any of them whom I sent unto you?

I desired Titus, and with him I sent a brother. Did Titus make a gain of you? walked we not in the same spirit? walked we not in the same steps?