“God has granted man a soul and a body, as well as the ability to be occupied and to glorify him with both. …After the fall it is also God’s will that man be occupied, and he appoints every man to his labor (1 Cor. 7:20). God wills that man not only perform his calling, but that he do so diligently.”
Brakel then talks about OT and NT words for diligence, and explains them like this: “This is expressive of dealing with a matter with utmost care and prudence for the purpose of assuring that the project might be executed and turn out well (Acts 18:25, Eph. 5:15, Luke 15:8, Rom. 12:8, etc.).”
“Diligence is the exertion of the spiritual and physical powers of a believer whereby he willingly, joyously, and earnestly executes that task which God assigns him, doing so because it is the will of God.”
“The essence of diligence consists in the exertion of the faculties of both soul and body. First, he engages his intellect to consider how he may best execute the task in the best manner (1 Sam. 16:18, Prov. 17:2, etc). Second, the will is engaged toward this duty in willingness and with joy (Ps. 100:2). Thirdly, the emotions and affections are also engaged (Ps. 119:60, Prov. 22:29). Fourthly, the diligent person engages the powers and faculties of the body for any physical labor to be engaged in (Ecc. 9:10).
The diligent person’s objective motivates him, and this in turn determines the means he uses to attain his objective: to do the will of God. He therefore dares neither to engage in any task which is sinful nor to make use of any sinful means for a task which in and of itself is neutral. This is the principle, substance, and purpose of all he does: he serves God (Eph. 6:5-7).
Brakel goes on to rebuke those who are lazy and not diligent and closes the discussion with an exhortation for Christians to be diligent. Why be diligent? 1) Because it is God’s command (1 Thess. 4:11-12, 2 Thess. 3:11-12), 2) Because diligence is an ornament to the Christian and to the church of God, 3) Because God gives us his own example of diligence (Ex 20:9-11, John 5:17), and 4) Because God promises his blessing upon diligence (Ps. 90:17, Prov. 10:4, 12:24, etc.).
Perhaps this could all be summarized by saying that whatever we do, we should do it to the glory of God (1 Cor. 10:31).
The above quotes are a summarized and edited version of Brakel’s discussion on diligence, found in The Christian’s Reasonable Service, volume 4, pages 103-109.