John 15:7 NASB
To abide means to reside with, to remain with, to submit to. When we reside with Jesus and submit to His words, we can ask whatever we wish. Why is this? When we abide in Him and He is us, we fulfill His command, which is love.
When we love God with all our heart, soul, strength and mind and love others the same way Jesus loves them, we aren’t going to be asking selfishly or with wrong motives. When Jesus prayed to the Father, it was always in perfect line with the Father’s will.
When we come to truly abide in Him and ask Him to abide in us, we will live in love and in complete agreement with the will of the Father.