The Promise of the Lord's Supper

The promise is valid now and forever, but i have to apply it to myself. I have to trust the promise that's given in the sacrament. So if i reject baptism, and i don't have faith, i have received baptism. It's valid. But in my heart, rejected it, therefore i've rejected my salvation. Because the promise is objective, i can come back to that promise and trust it in the future.