Hebrews 10:36

36.For ye have need of patience, etc. He says that patience is necessary, not only because we have to endure to the end, but as Satan has innumerable arts by which he harasses us; and hence except we possess extraordinary patience, we shall a thousand times be broken down before we come to the half of our course. The inheritance of eternal life is indeed certain to us, but as life is like a race, we ought to go on towards the goal. But in our way there are many hindrances and difficulties, which not only delay us, but which would also stop our course altogether, except we had great firmness of mind to pass through them. Satan craftily suggests every kind of trouble in order to discourage us. In short, Christians will never advance two paces without fainting, except they are sustained by patience. (196) This then is the only way or means by which we can firmly and constantly advance; we shall not otherwise obey God, nor even enjoy the promised inheritance, which is here by metonymy called the “promise”.