The interpretation timeline
Psalm 118:165 Douay-Rheims

Much peace have they that love thy law, and to them there is no stumbling block.

A.D. 430 – 1849 4 witnesses 5 excerpts

Patristic

before A.D. 750
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“"Great is the peace," he saith, "that they have who love Thy law: and there is no offence to them" (ver. 165). Doth this mean that the law itself is not an offence to them that love it, or that there is no offence from any source unto them that love the law? But both senses are rightly understood. For he who loveth the law of God, honoureth in it even what he doth not understand; and what seemeth to him to sound absurd, he judgeth rather that he doth not understand, and that there is some great meaning hidden: thus the law of God is not an offence to him...”
Source
“But who are they that the Church as the moon burneth by night? They that have made schisms. Hear the very word used in the apostle: "Who is offended, and I burn not?" In what sense then is it, that there is no scandal or occasion of stumbling in him that loveth his brother? Because he that loveth his brother, beareth all things for unity's sake; because it is in the unity of charity that brotherly love exists. Some one, I know not who, offendeth thee: whether it be a bad man, or as thou supposest a bad man, or as thou pretendest a bad man: and dost thou desert so many good men? What sort of brotherly love is that which hath appeared in these persons? While they accuse the Africans, they have deserted the whole world! What, were there no saints in the whole world? Or was it possible they should be condemned by you unheard? But oh! if ye loved your brethren, there would be none occasion of stumbling in you. Hear thou the Psalm, what it saith: "Great peace have they that love Thy law, and there is to them none occasion of stumbling." Great peace it saith there is for them that love the law of God, and that is why there is to them none occasion of stumbling. Those then who take scandal, or, occasion of stumbling, destroy peace. And of whom saith he that they take not and make not occasion of stumbling? They that love God's law. Consequently they are in charity. But some man will say, "He said it of them that love God's law, not of the brethren." Hear thou what the Lord saith: "A new commandment give I unto you that ye love one another." What is the Law but commandment? Moreover, how is it they do not take occasion of stumbling, but because they forbear one another? As Paul saith, "Forbearing one another in love, studying to keep the unity of the Spirit in the bond of peace." And to show that this is the law of Christ, hear the same apostle commending this very law. "Bear ye one another's burdens," saith he, "and so shall ye fulfill the law of Christ."”
Source
749
A.D.
John of Damascus Patristic
A.D. 676–749
“Obtain the same thing for yourself and strive to advance toward it; for it is able to raise you from earth to heaven. You will not advance in it without preparation or [solely] by chance. First cleanse your soul of every passion and wipe it as clean of every evil as a newly cleansed mirror. Remove far from you every recollection of wrong and anger, which most of all prevents our daily prayers from reaching God. Also remove from your heart the offenses of everyone who has ever sinned against you. Giving wings to your prayer with mercy and compassion for the poor, approach God with fervent tears. Praying in this way you will be able to say with the blessed David, who, although he was king and burdened with countless cares, cleansed his soul of all passions: "I hated and abhorred iniquity, but I loved your law. Seven times a day I praised you because of the judgments of your righteousness." My soul kept your testimonies and I loved them very much. Let my prayer draw near to you, Lord; enable me to understand your word.”
Source

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Let my supplication come before thee,.... The same with his "cry" in Psa 119:169; only expressed by another word, signifying a petition for grace and favour, in an humble and submissive manner; which it is entreated might be received and accepted, as before; deliver me according to thy word; of promise, such as that in Psa 50:15; meaning from all troubles and afflictions; out of the hands of all his enemies, and from the power of sin, Satan, and the world; and from all fears of wrath, ruin, and destruction. Kimchi observes, that this is not to be understood of a deliverance of the body from distress, but of the soul from the stumbling block of sin.”
Source
1849
A.D.
1774–1849
“Peace, in their own conscience, (Worthington) and prosperity, without fear of danger. Not even death can disturb those who belong to God, Romans viii. 38. (Calmet) — But all things work together for their good, Romans viii. 28. (Haydock) — The perfect are not moved to imitate bad example, and the weak are not excused for so doing, as they ought to be constant. (Worthington) — The virtuous man is neither scandalized at the law, though he may not understand it perfectly, nor at the fall of those who had been most eminent for sanctity. (St. Augustine)”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.