It harmonizes perfectly.
Christ died and reconciled all men to God but in the end, only a few stand saved. Means that it is what we do that makes us satnd or fall in the end. Those that abide in Christ's love and endure to the end are saved.
John 15:
5“I am the vine; you are the branches. If you remain in me and I in you, you will bear much fruit; apart from me you can do nothing.
6If you do not remain in me, you are like a branch that is thrown away and withers; such branches are picked up, thrown into the fire and burned.
7If you remain in me and my words remain in you, ask whatever you wish, and it will be done for you.
8This is to my Father’s glory, that you bear much fruit, showing yourselves to be my disciples.
9“As the Father has loved me, so have I loved you. Now remain in my love.
10If you keep my commands, you will remain in my love, just as I have kept my Father’s commands and remain in his love.