Hebrews 4:6-7

All the descendants of Abraham did not lose their opportunity to receive God’s inheritance because the generation of Israelites living during the wilderness wanderings failed God. In David’s day God re-extended His offer of entering rest, and that generation had to respond. The title of Psalms 95 in the Septuagint credited David with writing it. They had their "today" of opportunity also. Every generation of believers needs to continue to trust and obey to enter into our rest (inheritance).

"Tinas ["Some"] is generally explained as implying a warning that not all the readers are certain to receive what God promises (cf. . . ., Hebrews 3:12; also Hebrews 4:13; Hebrews 4:1; Hebrews 4:11 . . .)." [Note: Ellingworth, p. 250.]