Colossians 3:16 and Hebrews 10:25 give us an insight into what fellowship does to us which is to strengthen, admonish, and encourage one another.
As much as fellowship gives also gives us encounters, and we get to experience the move of God, spiritual growth steadily occurs in the secret place.
So, if you are never active in the secret place but only in church and meetings, then your spiritual life is stagnant. Growth occurs in the secret place after encounters and the move of God during fellowships