'Gain' in the Bible

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

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,

I begged Titus to visit you, and sent our other brother with him. Did Titus gain any selfish advantage over you? Were not he and I guided by one and the same Spirit, and did we not walk in the same steps?