Of uncertain affinity; compassion (human or divine, especially active) -- (+ tender) mercy.
STRONGS NT 1656: ἔλεος (2)ἔλεος (2), ἐλέους, τό (a form more common in Hellenistic Greek than the classic ὁ ἔλεος, which see), "mercy; kindness or good will toward the miserable and afflicted, joined with a desire to relieve them";
1. of men toward men: Matthew 9:13; Matthew 12:7; Matthew 23:23 (in these three passages, accusatives to L T Tr WH); James 2:13; James 3:17; ποιεῖν ἔλεος, to exercise the virtue of mercy, show oneself merciful, James 2:13; with the addition of μετά τίνος (in imitation of the very common Hebrew phrase פּ עִם חֶסֶד עָשָׂה, Genesis 21:23; Genesis 24:12; Judges 1:24, etc.; cf. Thiersch, De Pentateuchi vers. Alex., p. 147; (Winer's Grammar, 33 (32); 376 (353))), to show, afford, mercy to one, Luke 10:37.
2. of God toward men;
a. universally: Luke 1:50; in benedictions: Galatians 6:16; 1 Timothy 1:2; 2 Timothy 1:2; ((probably) Titus 1:4 R L); 2 John 1:3; Jude 1:2. ἐμεγάλυνε κύριος τό ἔλεος αὐτοῦ μετ' αὐτῆς, magnified his mercy toward her, i. e. showed distinguished mercy to her (after the Hebrew, see Genesis 19:19), Luke 1:58.
b. especially the mercy and clemency of God in providing and offering to men salvation by Christ: Luke 1:54; Romans 15:9; Ephesians 2:4; (Titus 3:5 L T Tr WH; Hebrews 4:16 L T Tr WH); 1 Peter 1:3; σπλάγχνα ἐλέους (the genitive of quality (cf. Winers Grammar, 611 (568))), wherein mercy dwells, as we should say, the heart of mercy, Luke 1:78; ποιεῖν ἔλεος μετά τίνος (see 1 above), Luke 1:72; σκεύη ἐλέους, vessels (fitted for the reception) of mercy, i. e. men whom GOd has made fit to obtain salvation through Christ, Romans 9:23; τῷ ὑμετέρῳ ἐληι, by (in consequence of, moved by) the mercy shown you in your conversion to Christ, Romans 11:31 (cf. Winers Grammar, § 22, 7 (cf. § 61, 3 a.); Buttmann, 157 (137)).
3. the mercy of Christ, whereby at his return to judgment he will bless true Christians with eternal life: Jude 1:21; (2 Timothy 1:16, 18 (on the repetition of κύριος in 2 Timothy 1:18 cf. Genesis 19:24; 1 Samuel 3:21; 1 Samuel 15:22; 2 Chronicles 7:2; Genesis 1:27, etc. Winer's Grammar, § 22, 2); but Prof. Grimm understands κύριος here as referring to God; see κύριος, c. α.). (Cf. Trench, § xlvii.; and see ἐληω at the end.)