“Then he remembered the days of old Moses, and his people, saying, Where is He that brought them up out of the sea with the shepherd of His flock? Where is He that put His Holy Spirit within him? That led them by the right hand of Moses with His glorious arm, dividing the water before them, to make Himself an everlasting name? That led them through the deep, as an horse in the wilderness, that they should not stumble? As a beast goeth down into the valley, the Spirit of the Lord caused him to rest: so didst Thou lead Thy people, to make Thyself a glorious name.”-Isaiah 63:11-14

I see, through the text, God’s great motive in working these wonders for His people. It was God who did it all. He brought them up out of the sea. He put His Holy Spirit within them. He led them with His glorious arm. He led them through the deep. He caused them to rest. He did it all. When the history of the church is written, there will be nothing on the page but God. I know that her sin is recorded; but He hath blotted that out; and at the end, there will remain nothing but what God has done. When your life and mine shall ring out as a psalm amid the harps of glory, it will be only, “Unto Him that loved us and laved us, be glory and dominion for ever and ever.” “Non nobis, Donine.” “Not unto us, O Lord, not unto us, but unto Thy name give glory.” So will sing all of us who are the Lord’s redeemed, when we have come up out of the great tribulation, and have washed our robes, and made them white in the blood of the Lamb.

But then, why had God done all this? Did He do it because of His people’s merits, or numbers, or capacities? He tells them, many a time, “Not for your sakes do I this, saith the Lord God, be it known unto you: be ashamed and confounded for your own ways, O house of Israel.” God finds in Himself the motive for blessing men who have no merits. If God looked for any motive in us, He would find none. He would see in us many reasons why He should condemn us; but only in Himself could He discover the motive for His matchless mercy. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2258.cfm