This is from the book "Endgame Strategy" by Mikhail Shereshevsky.

Chapter 5

"DO NOT HURRY"

The ability to make use of this principle demands of a player great experience in the playing of chess endings. How many endings have not been won, merely because the stronger side tried to win as quickly as possible, and neglected to make simple strengthening moves before embarking on positive action. Following the principle of "do not hurry", it is possible to battle for a win in positions with a slight but persistent advantage. Only in this way can a player achieve weakenings in the enemy position, mask his plans, and lull the opponent's vigilance.

But on no account should this principle be abused. One must be ready at the necessary moment to switch to sharp and positive action, otherwise the opponent may eliminate the weaknesses in his position, which are often of a temporary nature. The ability to sense and not miss this critical point is not something that comes easily. We will see in examples that in such situations even strong players often go wrong.

The logic behind the "do not hurry" principle is mainly psychological. It can be especially recommended to act according to this principle when the opponent is deprived of active counterplay.

Amazon - "Endgame Strategy" by Mikhail Shereshevsky