Below is one excellent sermon, given by the late David Wilkerson. It’s split into three videos, but all three are posted in order.
Hear, O LORD, when I cry with my voice: have mercy also upon me, and answer me. Psalm 27:7 (KJV)
When thou saidst, Seek ye my face; my heart said unto thee, Thy face, LORD, will I seek. Psalm 27:8 (KJV)
If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land. 2 Chronicles 7:14 (KJV)