2 Peter 1:8

“For if these things be in you, etc.] Are wrought in you by the Spirit of God, and exercised and performed by his assistance, who works in his people both to will and do: and abound; increase in their acts and exercises by the frequent performance of them: they make you; both by way of influence and evidence, [that ye shall] neither [be] barren nor unfruitful in the knowledge of our Lord Jesus Christ. There is a knowledge of Christ which is barren and fruitless; and those that have it are so in their conversations, and it will be of no avail to them another day: and this is a mere notional and speculative knowledge, such as is not attended with any inward experience and application of Christ…”

“be--Greek, "subsist" that is, supposing these things to have an actual subsistence in you; "be" would express the mere matter-of-fact being (Act 16:20). abound--more than in others; so the Greek. make--"render," "constitute you," habitually, by the very fact of possessing these graces. barren--"inactive," and, as a field lying fallow and unworked (Greek), so barren and useless. unfruitful in--rather, . . . in respect to, "The full knowledge (Greek) of Christ" is the goal towards which all these graces tend. As their subsisting in us constitutes us not barren or idle, so their abounding in us constitutes us not unfruitful in respect to it. It is through doing His will, and so becoming like…”

“For if these things be in you, and abound - If they are in you in rich abundance; if you are eminent for these things. They make you that ye shall neither be barren nor unfruitful - They will show that you are not barren or unfruitful. The word rendered “barren,” is, in the margin, “idle.” The word “idle” more accurately expresses the sense of the original. The meaning is, that if they evinced these things, it would show. (1)That they were diligent in cultivating the Christian graces, and, (2)That it was not a vain thing to attempt to grow in knowledge and virtue. Their efforts would be followed by such happy results as to be an encouragement to exertion. In nothing is there, in fact, more…”

“For these being really in you - Added to your faith. And abounding - Increasing more and more, otherwise we fall short. Make you neither slothful nor unfruitful - Do not suffer you to be faint in your mind, or without fruit in your lives. If there is less faithfulness, less care and watchfulness, since we were pardoned, than there was before, and less diligence, less outward obedience, than when we were seeking remission of sin, we are both slothful and unfruitful in the knowledge of Christ, that is, in the faith, which then cannot work by love. 2 Peter 1:9”

“in you: Joh 5:42; Co2 9:14, Co2 13:5; Phi 2:5; Col 3:16; Plm 1:6 and abound: Co1 15:58; Co2 8:2, Co2 8:7; Phi 1:9; Col 2:7, Col 3:16; Th1 3:12, Th1 4:1; Th2 1:3 they: Joh 15:7, Joh 15:8; Co2 5:13-17 barren: or, idle, Pro 19:15; Mat 20:3, Mat 20:6, Mat 25:26; Rom 12:11; Ti1 5:13; Heb 6:12 unfruitful: Mat 13:22; Joh 15:2, Joh 15:6; Tit 3:14 in: Pe2 1:2 2 Peter 1:9”