Charles H. Spurgeon on Psalms 119:75

Thou in faithfulness hast afflicted me. Mark the emphasis: he doth not barely acknowledge that God was faithful, though or notwithstanding he had afflicted him, but faithful in sending the afflictions. Affliction and trouble are not only consistent with God's love plighted in the covenant of grace; but they are parts and branches of the new covenant administration. God is not only faithful notwithstanding afflictions, but faithful in sending them. There is a difference between these two: the one is like an exception to the rule, quae firmat regulam in non exceptis:the other makes it a part of the rule, God cannot be faithful without doing all things that tend to our good and eternal welfare. The conduct of his providence is one part of the covenant engagement; as to pardon our sins, and sanctify us, and give us glory at the last, so to suit his providence as our need and profit require in the way to heaven. It is an act of his sovereign mercy which he hath promised to his people, to use such discipline as conduces to their safety. In short, the cross is not an exception to the grace of the covenant, but a part of the grace of the covenant.

The cause of all afflictions is sin, therefore justice must be acknowledged: their end is repentance, and therefore faithfulness must be acknowledged. The end is not destruction and ruin, so afflictions would be acts of justice, as upon the wicked; but that we may be fit to receive the promises, and so they are acts of faithfulness. Thomas Mantel.