The two huge mountains in Christianity are the Great commandment and the Great commission.
A) Great commandment: Love God with all your mind (intellect), soul (feelings/emotions ) , heart (will) & strength and love your neighbour as yourself.
Show love, live in love and demonstrate love.
B) Great commission: Don't evangelise but disciple. To evangelise is to proclaim, to disciple is to make into the image and likeness of Christ.
The bridge between the two mountains is the Church. Jesus started and the Body will continue with the work.