No one religion has a monopoly on lovingkindness, and each has something to offer those who have made the choice for heaven. I encourage you to study broadly in the world's religions and adapt what you need from wherever it is found.
It is not enough to be versed in only one religion. You are heir to the entire spectrum of human spirituality. While one of them may resonate more strongly within you than another, you can learn from them all and adapt practices from each to enrich your own capacity for lovingkindness.
— Rami Shapiro, The Sacred Art of Lovingkindness