The ability of believers to cry ‘Abba, Father’ is evidence that they have been adopted, for only by the Spirit can they cry out like this. But don’t many people call God their Father who have no right to do so, who have not truly been born again? Yes, but Paul is speaking of a cry that comes from the heart and not from the lips only. He is speaking of what lies behind that cry: the awareness of being the children of God, which the Spirit alone gives. The convert to Christ discovers prayer as a new instinct within him, so that everything is brought to his Father in heaven. He alone has power to answer the many insurmountable problems we face, and in particular he alone can help the soul in the deep waters it must pass through. This is not presumption, even if through the weakness of the flesh we sin and must confess our sins on a daily basis. We now have a delight in God’s law after the inward man, and we are grieved by our falls as we never were before, not simply out of fear of punishment but because we sense that the Spirit within us is grieved.
Although experience must never be placed above the word of God, there is such a thing as true Christian experience. Some people wish to say that this or that has happened to them, and God has done this or that in their lives, but the things they speak of are peculiar to themselves, and no one else in the Bible is ever recorded as experiencing such things; these claims are not tested by the Scripture and so are of little worth. But where experience is backed up the Scripture it has great power to instruct us in the way God works, and it is a strong source of assurance to us.