ISB ~ Hebrews 12 v14

Strive for peace:So far as it depends on the believer, who might be tempted to return evil for evil to his persecutors (Rom 12:14-18).

holiness:Personal sanctification is required for attaining the vision of God in heaven (Mt 5:8; Rev 22:4). This includes being made holy or sanctified by the grace of God, first of all in Baptism (1 Cor 6:11). However, the Lord also wills us to “strive” for an increase in sanctification by the exertion of our will in living the gospel to the full (Rom 6:19; 1 Thess 3:12-13; 4:3). The text declares this second aspect of holiness to be indispensable for reaching heaven.