A crisis that threatened a Philippian jailer with death prompted him freely to ask Paul and Silas the most important question in life: “What must I do to be saved?” (Acts 16:30) This question about God's requirement for salvation (GRFS) is most important, because—as sinful and mortal souls—we need saving from corruption, both moral and physical. We need saving from physical death if we value or enjoy life, and we need saving from immorality or evil-doing if it results in unhappy existence, especially after this lifetime.
The reply of Paul and Silas was this: “IF you [freely choose to] believe in the Lord Jesus, you will be saved.” (Acts 16:31) This is GRFS in a nutshell. IF connotes God’s condition for repentance (cf. the IFs in John 8:7, 14, 16, 19, 24, 31, 36, 39, 42, 46, 51, 54, 55). Jesus Himself expressed GRFS even more succinctly using three, four and five letter words: “Ask… seek… knock…” (Matt. 7:7). This indicates that God enables/gives every sinful soul the ability and opportunity (exercising moral free will/MFW) to repent of sin (Matt. 4:17) and seek salvation (1Tim. 2:3-4, Ezek. 33:11), which might be called “seeking grace” (Tit. 2:11, Eph. 2:8). As Heb. 11:6 states: “he [God] rewards those who earnestly seek him” (cf. Isa. 45:19).
Seeking God/Truth is the beginning of saving faith (2Thes. 2:10), and not seeking God or rejecting His salvation in Christ is the essence of evil atheism or faith in I-dolatry (Rom. 3:11, 1:18-23). All humans sin, but every sinner has the opportunity (via MFW) to repent/have saving faith per God's Word: Gen. 3:6, Deut. 30:19, Josh. 24:15, 2Chron. 7:14, Matt. 4:17, 7:7, 23:37, John 3:16, 6:39, Acts 2:38, 16:31, 28:27, Rom. 1:20, 2:4, 11&15, 3:22, 4:23-24, 5:15&19, 10:9-13, 11:32, Gal. 3:8&14, Eph. 2:8-9, Phil. 2:10-11, Col. 1:19-23, 1Tim. 2:3-4, etc.