In whom we have redemption through His blood, the forgiveness of sins… – Ephesians 1:7

“Redemption through His blood.” Observe, it is not redemption through His power, it is through His blood. It is not redemption through His love, it is through His blood. This is insisted upon emphatically, since in order for the forgiveness of sins it is redemption through His blood, as you have it over and over again in Scripture. “Without shedding of blood is no remission.” But they say-they say-that substitution is not just. They say, “Let God simply forgive the sin, and have done with it.” But where, then, were His justice? “Shall not the Judge of the earth do right?” He threatened sin with punishment. If He does not execute His threatening, what then? Can we be sure that He will fulfill His promise? If He break His word one way might He not break it another? If the Lord should not execute the penalty which He has threatened to sin, would it not look as if He made a mistake in threatening a penalty at all? Would it not seem as if He had been too severe at the first, and then had to catch Himself up, and revise His own judgment afterwards? And shall that be? Might it not be supposed that, after all, God made much ado about nothing, and that He was really jesting with men when He threatened them with fearful punishment on account of sin? Shall God say, “Yea,” and “Nay”? Shall He speak and unspeak? This is according to the folly of man. Sometimes it may even be wisdom in a fallible man to reverse his word and retract his declaration; but with God this cannot be. It is needful for the vindication of His own justice, His wisdom, and His holiness, that He shall not forego one of His threatenings, any more than one of His promises; and, since it is just that sin should be punished, and that, though the sinner should in wondrous mercy be permitted to go free, it is wise and just that Another should step in-God’s own Self should step in-and bear for the sinner what is due to the justice of the Most High. ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/2207.cfm