Charles H. Spurgeon on Psalms 71:8

Let my mouth be filled with thy praise. Let my mouth, I say, be so filled with thy praise, that from the bottom of my heart, even to the lips of my mouth, the plenitude of thy grace, O God, infused into my heart, and diffused over my lips, may loyally magnify thee; so shall I not be found like that people, of whom thou dost say: "This people honour me with their lips, but their heart is far from me." Isa 29:13. Gerhohus.