Earlier the writer had described his readers as being sluggish (lit. lazy, Hebrews 5:11). Now he urged them to be diligent and to stop being lazy ( Hebrews 6:12; cf. Proverbs 24:30-34; 2 Peter 1:5; 2 Peter 1:10). The same Greek word (nothroi) occurs in both places. He wanted them to remain faithful to God while waiting patiently for Him to fulfill His promises to them regarding their future inheritance. [source][source][source]
"The theme of imitation recurs in Hebrews 13:7, and in both instances faith is seen as steadfast persistence that pursues the divine promise ..." [1][source]
Some commentators have used this verse to support the unbiblical idea that believers should look to their good works as evidence of their election and as the basis for their assurance of salvation. This verse is not saying that. The Greek word plerophoria always means "fullness" in the passive sense, not "fulfilling." The writer meant that we need to be diligent regarding something we have already obtained, not to obtain something, namely, assurance. [2][source]
Note the linking of love ( Hebrews 6:10), hope ( Hebrews 6:11), and faith (v12) here (cf. Hebrews 10:22-24). This triad occurs often in the New Testament epistles (cf. Romans 5:2-5; 1 Corinthians 13:13; Galatians 5:5-6; Colossians 1:4-5; 1 Thessalonians 1:3; 1 Thessalonians 5:8; 1 Peter 1:21-22). [source][source][source]