"Faith" comes before "feelings" in the dictionary, and so it does in the matter of our spiritual blessing.
Many would like to reverse it. They would like to feel happy before in simple faith they have taken God at His word, but God would not have our assurance of salvation to rest on such a flimsy foundation as our feelings. He would have us rest on Christ and His atoning sacrifice.
Feelings ebb and flow and come and go like the tides that wash the shore. Christ's work is abiding. God's way is unchanging. It has been put something like this: The Lord Jesus did it—the holy God says it—I, the sinner, believe it.
The Lord Jesus did what? Suffered for sins upon Calvary's cross. He finished the mighty work of eternal redemption.
The holy God says what? That "Whosoever believeth in Him (the Lord Jesus) shall receive remission of sins."
I, the sinner, believe what? I believe what God says about His Son and what He has done, and I know that forgiveness of sins is mine.
Why did the Lord Jesus do it? Because there was no other way in which we could be blessed.
Why does God say it? Because the Lord Jesus did it all at Calvary.
Why do I believe it? Because God says it. Not because I feel anything this way or that, simply and only because God says it.
Happy feelings depend upon our faith in Christ's sacrifice and in God's Word about it.