In Divine Friendship by Swami Kriyananda
How to Measure Your Spiritual Progress
The more deeply you enjoy the peace of meditation, the more satisfactory will be your progress.
Spiritual advancement can be judged also by how free you feel from the constant goading of egoic individuality: the hurts, whether large or small; the pains of life, both physical and mental; the desire for recognition, fame, or worldly power and importance; by how little you refer your painful or pleasant experiences back to yourself, thinking, “I am the one suffering or exulting”; by your inner freedom from desires of all kinds except the longing for God; by how free you feel from every test, including those of blame, opposition, and calumny on the one hand, or praise, popularity, and fame on the other; by your inner freedom from identification with success or failure, in the recognition that, in cosmic reality, all human experiences are essentially equal.
You are advancing when you see all others as allied to your own Self, and your sense of identity expands to include everything. All the above are signs that one is advancing spiritually.
The most important sign is this: that your love for God is growing ever deeper, and you feel selfless joy in the thought of Him — or, better still — in the actual perception of Him.