The Chida zt’l (Hagadah Shel Pesach Peh Achas) explains the words we recite in the Hagadah: ‘Anyone who is hungry should come and eat… We are currently here; next year in Yerushalaim’ by quoting Mekubalim who say that when a person accepts to help the poor, the gate of mercy open for him in Heaven and he is provided with an abundance of blessing even before he gives his donation to the poor.
Accordingly, we say that everyone in need is invited to our house. We then say that ‘we currently are here’, meaning that this is what we do while in golus. However, we accept to do this next year in Yerushalaim, and with this acceptance, the gates of mercy are opened for us. In the merit of our tzedakah, we will be free men next year, having experienced the ultimate redemption.