This portion of our reading through the book of Hebrews contains an exhortation and a warning.
We are exhorted to seek the true rest of the Lord, while warned not to make the mistake of the rebellious people of Israel, who hardened their hearts against the Lord, and did not enter into His rest.
Christ Jesus is the “great High Priest who has passed through the heavens” (Heb 4:14), so that we may now enter His Sabbath rest by faith in His forgiveness (Hebrews 4:3–9).
Collect for Thursday of the week of Pentecost 21: We thank thee, O God, for thy Holy Spirit, who incites us to true knowledge of thee. We humbly entrust thee for thy Son’s sake to illumine our hearts with thy Holy Spirit that we may truly call upon thee, know thee, sincerely believe in thee, give thanks to thee, and obey. Let not the light of thy gospel be taken from us through deceitful illusions. Direct us in all our affairs with the voice of thy counsel, for thy Son has promised that thou wouldst give thy Holy Spirit to those who ask Grant this, O God, for thy holy name’s sake. To thee, with thy Son and the Holy Spirit, be all honor and glory forever.  Amen –Philip Melanchthon - 14 October 2021
 Collect for Thursday of the week of Pentecost 21, For All the Saints, A Prayer Book For and By the Church, Vol. IV © 1996 The American Lutheran Publicity Bureau, Delhi, NY