The R-word
The R-word (repentance) is the first step toward the re-centering of, retuning to, and revival from God.
In 1 Samuel 7 we see where the Jews had drifted from God and even from their faith. After 20 years of the Ark being displaced from the center of Jewish life, the Jews began to lament after God. Samuel told them that if they truly wanted to return to God with all their heart, then they had to repent (change). They had to repent in mind, heart, and action. He told them to put away (forsake) their idols, direct their hearts to God (confession of sin), and serve (worship, love, obey, follow, etc.) God only.
Samuel's remedy was applied, and God brought renewed fellowship among the people and even more He brought deliverance from their oppressors. When we repent and re-center God in our focus, attention, priorities, worship, obedience, etc., then God brings revival and deliverance into our lives.