What a wonderful advertisement for the necessity of Union! As Believers, our desire is that we might make Jesus known in every day, situation, context or gathering in which we find ourselves. Oftentimes we enter into our day and wonder how we should act, what we should say etc, in order to fulfill that end...
Yet if the truest thing about us is that Jesus lives inside us, the "problem" expressed in Mark 7 becomes our daily life experience: We'll enter a house, or a meeting, or a coffee shop, or a doctor's office, or our children's school, or a sporting event, and Jesus, the One living inside us, will be unable to keep His Presence there secret.
O Believer, your Union-with-Him is His highest idea for the evangelization of the world. It is your only work in that arena. From it springs the fullness of the fruits that He is working to grow in you, tend in you and bear forth into this world that so desperately needs Him.
"Abide in Me, and I in you..."