Not only does much time elapse between the promise and the possession of the matter which hope assuredly anticipates, but also much opposition from enemies is to be expected. Therefore, the person who exercises hope needs to be valiant in order to endure all things and overcome all obstacles. We thus add to hope spiritual strength or courage.
Spiritual strength is an undaunted steadfastness of heart, given by God to His children, whereby they, while entertaining a lively hope of acquiring the promised benefits, overcome fear for all danger and opposition, unyieldingly engage in warfare, and courageously persevere in obedience toward God.
The following is a true proverb: Ardua quae pulchra, or, eminent matters are difficult to be obtained. This is true in both natural and spiritual matters. Those spiritual matters to be acquired are most eminent. He who is not acquainted with them, however, will neither trouble himself about them, nor risk any danger for them; but he who is acquainted with them will risk everything for them and will fortify his heart with hope. This fortitude, even though the world designates it as being stubborn and strong-willed, is nevertheless an eminent virtue. It is an ornament for the Christian which is pleasing to God, dreadful to the world, and personally beneficial. It is a virtue which God requires and to which believers are frequently exhorted, namely, “Be strong.”
The seat of spiritual strength is to be found in the soul, intellect, will, and affections of the believer. All of these are fully engaged relative to the objects at hand. It is not a physical activity (even though this is also essential in the execution of this strength), but rather an activity of the soul. It is not merely an activity of the intellect, observing this virtue in its beauty, but all faculties are active. It is not an activity which is occasionally engaged in, but rather it is a propensity, a habitual disposition and competence, which initially is infused by God, but which is exercised by the influence of the Holy Spirit, and by much exercise improves and becomes stronger. “His heart is fixed, trusting in the Lord. His heart is established, he shall not be afraid” (Ps 112:7-8). The heart of the unconverted is not the subject of this strength, for they are unto all good work reprobate (Titus 1:16). They have no promise, no faith, no hope, nor internal spiritual life. What spiritual strength and courage could they then have? Only the regenerate are the courageous ones and they have what we have just mentioned—something which the unconverted do not have. All “the righteous are bold as a lion” (Prov 28:1). To those who are called to be saintsthe apostle says, “Quit you like men, be strong” (1 Cor 16:13).
Both object and goal are identical here. Spiritual strength relates to the good that is to be acquired and the evil that is to be overcome. God promises many benefits to His own according to body and soul, doing so, however, upon the condition that they will be acquired via the means commanded and ordained by God. The spiritually valiant person is acquainted with them, loves them, believes the promises, and anticipates them in hope. With this perspective he initiates his endeavor, follows after it, and seeks to apprehend it. In this work much resistance is encountered: loss of honor, possessions, and even life. One will encounter shame, contempt, ridicule, hatred, opposition from every perspective, poverty, illness, and all manner of adversity. All of that has the potential to engender fear, and through fear to cause either full or partial cessation of the endeavor. Spiritual courage will not yield, however, but will persevere all the more vehemently. It cannot be moved by anything; it does not even count life dear (Acts 20:24). While thus engaged, the soul may suffer from spiritual desertion and strife. Faith may be assaulted, and hope both shaken and tossed to and fro, so that the inner turmoil is frequently overwhelming. The courageous person, however, proceeds as if blind, does not succumb, keeps courage, and battles as a courageous hero, defending himself and inflicting injury to the enemies. However, an additional evil arises—an evil which has a more far-reaching effect than the previous evil: the old Adam. It flatters, entices, and causes the person to go astray. Here he stumbles, there he falls, then he receives a grievous wound and then again a deadly wound in his soul. That which is good is neglected, the evil is committed, and this is able to make a spiritual soldier unbelieving concerning his state, and cause him to feel hopeless and become discouraged. However, spiritual strength looks beyond that as well. If the believer cannot remain upright with his burden, he will crawl with it, and if he succumbs to it, he will rise again and renew the battle with new courage. If he cannot see his way through, he believes in and relies upon the Lord Jesus, commends the outcome to Him, and is determined to persevere, regardless of what the cost may be. If the enemy is too strong and he is overcome, he will nevertheless do his best and not surrender—he who is put to the worst in the battle is also fighting. Thus, both good and evil are the objects of the activity of spiritual strength.